WO2021194429A1

WO2021194429A1 - Spectrally adjustable luminaire that mimics daylight and takes into account the age of the user

Info

Publication number: WO2021194429A1
Application number: PCT/SI2021/050002
Authority: WO
Inventors: Katja MALOVRH REBEC; Andrijana SEVER SKAPIN; Andraz LEGAT; Friderik KNEZ; Marino FURLAN; Rok PERIC; Dimitrij ZIVEC
Original assignee: Intra Lighting D.O.O.; Zavod Za Gradbenistvo Slovenije
Priority date: 2020-03-27
Filing date: 2021-01-20
Publication date: 2021-09-30
Also published as: SI25985A; EP4129007A1

Abstract

The subject of the invention is a spectrally adjustable luminaire that mimics daylight at a given moment and in parallel may take into account the age of the user so that the spectrum of light emitted by the luminaire is properly corrected in that part of the spectrum directly related to spectral transmittance of the user's lens, which changes with the age of the user. The spectrally adjustable luminaire with appropriate LED control adjusts the output spectrum, which is a mixture of spectra emitted by individual LEDs, to the desired spectrum, so that the output spectrum matches the desired spectrum as closely as possible. The desired spectrum refers to the spectrum of light mimicking the spectrum of daylight at a particular part of the day and is simultaneously corrected for the user's age. The matching of the output spectrum with the desired spectrum is evaluated by the method of direct matching of both spectra and is expressed by the value of R². A higher value of R² means a greater match of the two spectra. The luminaire according to the invention makes it possible for the output spectrum of the luminaire to match the desired spectrum at a value of R² of at least 0.7 for a warm white solution and at a value of R² of at least 0.5 for a cool white solution.

Description

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Spectrally adjustable luminaire that mimics daylight and takes into account the age of the user

Introduction / Subject of invention

The subject of the invention is a spectrally adjustable luminaire that mimics daylight at a given moment and also takes into account the age of the user so that the spectrum of light emitted by the luminaire is properly corrected in that part of the spectrum directly related to spectral transmittance of the user's lens, which changes with the age of the user. The spectrally adjustable luminaire with appropriate LED control adjusts each specific output spectrum, which is a mixture of spectra emitted by individual LEDs, so that the output spectrum matches the desired spectrum as closely as possible. In the context of this application, the term "desired spectrum" refers to a spectrum of light that mimics the spectrum of daylight at a particular part of the day and is simultaneously corrected for the user's age by calculating the stimulation of all five photoreceptors. For example, with age, the spectral transmittance of a user's lens changes, and this calculated correction is taken into account in the desired spectrum, so that the spectrum is enriched in that part which the lens filters out with age. In the context of this application, the term "output spectrum" refers to the spectrum of light emitted by a luminaire at a given time. It is desirable that the output spectrum matches the desired spectrum as much as possible. The matching of the output spectrum with the desired spectrum is evaluated by the method of direct matching of both spectra and expressed by the value of R², which is between 0.0 and 1.0. A higher value of R² means a greater match of the two spectra. Both spectra are illustrated by a curve of the spectral density of the radiant flux as a function of wavelength.

Demonstration of a technical problem solved by the invention and for which patent protection is claimed

Light-emitting diodes (LEDs) make it possible to change the spectral composition of the emitted light in two ways. Light can be modulated with filters, yet there appears a problem of loss of certain wavelengths or increased energy consumption. Light can also be modulated by combining different sources, wherein light-emitting diodes emitting light of different wavelengths are mostly combined with luminophors. The latter provide a wider range of emitted light across the wavelengths, as a monochrome light-emitting diode usually emits light in a frame spectral width of 10 nm to 20 nm. The problem with the spectrally adjustable luminaires currently available is that the emitted light is evaluated only with the Correlated Colour Temperature (CCT). The latter, however, is not an appropriate way to illustrate differences in the spectral composition of the emitted light of light sources, since different light sources have the same colour temperature, hereinafter CCT, but different spectral composition of the emitted light. Figure 1 shows four different light sources, namely daylight - D27, energy saving lamps - CFL, light-emitting diodes - LED and halogen source, which have a comparable colour temperature - CCT is about 2700 K, but their spectral composition is significantly different.

Differences in spectra, despite the same CCT value, are important because they affect both image and non-image perception of the user. The human eye contains five types of photoreceptors, in addition to rods and three types of cones for image or visual perception, light-sensitive ganglion cells (ipRGC - intrinsically photosensitive retinal ganglion cells) for non-image perception. These cells are known to be essential for regulating daytime/night time or circadian rhythms. Circadian rhythm disorders directly affect the deficient/excessive production of melatonin, and thus the well-being of the individual and the emergence and development of various pathophysiological conditions in humans (e.g. insomnia and even various forms of cancer). In fact, melatonin has antioxidant and anticarcinogenic effects. The effects of changes in the transmittance of the human lens over the years on non-image perception are described in the paper "High-performance lighting evaluated by photobiological parameters" by K. Malovrh Rebec and M. Klanjsek Gunde (Applied Optics, 10.8.2014, Vol 53, No. 23). Due to the influence on the melatonin formation/release, the light spectrum is also related to the user's productivity in performing activities, for example, if the intensity is increased in the blue part of the spectrum, the user's productivity increases.

In similar CCTs, there are differences in photoreceptor stimulation at individual light sources. Although photoreceptors for image perception cumulatively do not detect these differences, a sensitive observer detects the differences but does not know the cause for them. In contrast, very large differences arise in photoreceptor stimulation for non-image perception.

The areas of action curves of photoreceptors for image or visual perception overlap, so, due to differences in the spectral distribution of light, the effects in the stimulation of these photoreceptors are much less perceptible than in the stimulation of a photoreceptor for non image perception, which is a single one. The peak sensitivity of the photoreceptor for non image perception on the cornea is at 480 nm, that is in the blue part of the visible light spectrum. An additional problem is the change in the transmittance of the human lens with age. The lens is spectrally variable, more precisely the transmittance of the human lens decreases much more significantly with age in the blue part of the spectrum than in the green, yellow and red parts of the spectrum. It is therefore desirable that the emitted spectrum of a luminaire be adapted to the user’s age, for example for older users, the emitted spectrum of a luminaire is adequately enriched in the blue part of the spectrum. An example of the methodology of appropriate spectrum adjustment, i.e. how much it is necessary to enrich the blue part of the spectrum depending on the user’s age, and thus the corresponding correction of daylight spectrum is described in “Optical properties, photobiological and environmental impacts of lamps with light-emitting diodes’’· doctoral dissertation, [K. Malovrh Rebec], 2014 COBISS.SI-ID - 275459584.

When designing spectrally adjustable luminaires, it is important to take into account the non-image perception of the human eye, changes in the transmittance of the human lens over the years and differences in the spectral composition of daylight depending on location, time of year, atmospheric pollution, etc.

Prior art

There exist spectrally adjustable luminaires that allow adjusting the spectral composition of the emitted light according to the CCT value, which in practice does not reflect the actual spectral match with the desired spectrum, where differences due to different stimulation of user photoreceptors would be taken into account. Solutions on the market that advertise daylight imitation do not mimic the curves of the spectral distribution of daylight, but mimic the colour of light ostensibly, that is, with a cumulative effect on image perception, while non-image differences can be large. As described in the previous chapter, this can be a major problem primarily for human health.

Patent No. EP1046196 B2 describes a solution where different CCTs are obtained by combining light sources with different spectra. The system includes at least two light- emitting diodes that emit visible light at selected wavelengths. The system also includes luminescent material that is sensitive to light with a wavelength of 400 nm to 500 nm or 500 nm to 560 nm. In one preferred embodiment, the system includes a blue light-emitting diode, a red light-emitting diode, and a luminescent material that is sensitive to light with a wavelength of 400 nm to 500 nm and can be excited by blue light and converts blue light to green light. In another preferred embodiment, the system includes a blue light-emitting diode, a green light-emitting diode, and a luminescent material that is sensitive to light with a wavelength of 500 nm to 560 nm and can be excited by green light and converts green light to red light.

Patent No. EP1610593 describes a lighting fixture for generating white light, said fixture comprising: a plurality of component illumination sources comprising a first component of the light source including at least one first white LED with a first spectrum, and a second component light source comprising at least one secondary white LED with a second spectrum, the first spectrum being different from the second spectrum, a data link for receiving data from an external source, and a processor, the processor being controlled by data to control the plurality of light source components, the processor being adapted to control the first intensity of at least one first white LED with the first spectrum and the second intensity of at least one second white LED with the second spectrum, so that the colour temperature of the white light generated by the fixture can be controlled.

Patent No. EP1887836 describes a protection for controlling the spectral composition, which may be supported by sensor detection. With processor-controlled LEDs combined with diffuse materials, a number of beneficial effects of colour changes of light for display and illumination can be created. The systems described herein can be used to autonomously change the colour of light and thus colour effects on various consumer products and other household items. The system can also include sensors so that the spectrum of light emitted by the LEDs varies according to environmental conditions or user input. In addition, the system may include an interface for connection to the network so that the spectrum of light emitted by the LEDs is controlled via the network.

A lamp that would mimic the spectral curve of the emitted photons of daylight and at the same time correct the output spectrum depending on the age of the human lens is not available on the market.

Description of the solution to the technical problem

The invention will be described hereinbelow and illustrated on the figures which show: Figure 1 shows a spectral composition of four different sources that have a similar CCT

Figure 2 shows a comparison between the desired spectrum and the output spectrum for users of different ages for the cool white solution

Figure 3 shows a comparison between the desired spectrum and the output spectrum for users of different ages for the warm white solution

Figure 4 shows an embodiment of a block diagram of the luminaire of the invention Figure 5 shows an embodiment of a 3D design of the luminaire Figure 6 shows an embodiment of a single basic LED module.

The spectrally adjustable luminaire according to the invention uses warm white light- emitting diodes and cool white light-emitting diodes as primary sources for daylight simulation, hereinafter primary light-emitting diodes, which can mimic daylight throughout the day in terms of cumulative stimulation of three photoreceptors for image perception. Warm white LEDs seem to mimic daylight at sunrise or sunset, while cool white LEDs mimic daylight in the middle of the day. Adaptation of the output spectrum of the light emitted by these diodes to each specific desired spectrum, i.e. the light spectrum that mimics the spectrum of daylight at a certain part of the day and is simultaneously corrected according to the age of the user, is made possible by additional monochrome light-emitting diodes in the blue part of the spectrum, hereinafter referred to as the blue light-emitting diodes, and with monochrome light-emitting diodes in the red part of the spectrum, hereinafter referred to as the red light-emitting diodes. Adaptation of the output spectrum to the desired spectrum is enabled by appropriate control of the light-emitting diodes. The control of the light-emitting diodes is performed via an external control unit, which regulates the intensity of each type of light-emitting diodes via a multi-channel power supply, so that it regulates the power supply current of each light-emitting diode. In this way, it is made possible for the output spectrum to match the desired spectrum as much as possible. The spectrum of sunlight (daylight) changes during the day. In the context of this application, the warm white solution refers to the spectrum of sunlight at sunrise or sunset (according to the CCT classification at 2700 K), the cool white solution refers to the mid-day sunlight spectrum (according to the CCT classification at 6500 K).

The matching of a respective output spectrum of the luminaire with a respective desired spectrum, where both spectra are illustrated by the curve of the spectral density of the radiant flux as a function of wavelength, is evaluated by the method of direct matching of both spectra ("goodness of fit”) and is expressed by the value of R², which is between 0.0 and 1.0. R² is the coefficient of determination, which gives information about the extent to which the output spectrum matches the desired spectrum. A higher value of R² means a greater match of the two spectra, wherein the value of 1.0 means perfect match. The luminaire according to the invention makes it possible for the output spectrum of the luminaire to match the desired spectrum at a value of R² of at least 0.7 for a warm white solution and at a value of R² of at least 0.5 for a cool white solution.

The spectrally adjustable luminaire according to the invention, presented in Figures 4 to 6, includes:

- at least one warm white light-emitting diode 34, at least one cool white light-emitting diode 33, at least one blue light-emitting diode 35, 37 and at least one red light-emitting diode 36, 38;

- a power supply 2 for supplying the light-emitting diodes, and

- a control unit 4 including at least a controller 41 for controlling the light-emitting diodes via the power supply 2, and a memory unit 42, the memory unit 42 including a plurality of memory locations for storing data on the desired spectra, including data on the associated intensities of power supply currents for controlling the individual light-emitting diodes 33-38 to achieve the desired spectra, the corresponding intensities of the power supply currents in the memory locations being either predetermined according to the pre-set desired spectra or at a given moment determined according to the pre-set desired spectra and the actual light in the room, wherein the controller 41 , depending on the selected spectrum based on the data of the desired spectra stored in the memory unit 42 and the corresponding power supply currents for controlling the individual light-emitting diodes 33-38, controls the power supply 2 for supplying the light-emitting diodes 33-38, the intensity of the power supply current of a particular light-emitting diode 33-38 being determined in a way that the output spectrum of the luminaire matches the desired spectrum at a value of R² of at least 0.7 for a warm white solution and at a value of R² of at least 0.5 for a cool white solution, the value of R² being determined by the method of direct matching of both spectra.

In a preferred embodiment, the luminaire according to the invention includes one warm white light-emitting diode 34 with a colour temperature of 2700 K and one cool white light- emitting diode 33 with a colour temperature of 5000 K. In a preferred embodiment, the luminaire according to the invention also includes two blue light-emitting diodes 35, 37, the first blue light-emitting diode 35 having an emitted peak at 430 nm, the second blue light- emitting diode 37 at 480 nm, and two red light-emitting diodes 36, 38, the first red light- emitting diode 36 having an emitted peak at 650 nm and the second red light-emitting diode 38 at 730 nm.

As already mentioned, the warm white light-emitting diode 34 and the cool white light- emitting diode 33 are the primary light-emitting diodes and serve as the primary sources to mimic daylight. The warm white light-emitting diode 34 has a colour temperature of 2700 K, as this light-emitting diode can best reproduce daylight at sunrise or sunset, the cool white light-emitting diode 33 has a colour temperature of 5000 K, as this light-emitting diode can best reproduce daylight in the middle of the day. So, with the selected light-emitting diodes, daylight can be reproduced throughout the day.

The red light-emitting diodes 35, 37 emit light in the red part of the spectrum in the range between 650 nm to 730 nm, the blue light-emitting diodes 36, 38 emit light in the blue part of the spectrum in the range between 420 nm to 480 nm.

Using additional red 35, 37 and blue light-emitting diodes 36, 38, the spectra of the two primary light-emitting diodes 34 and 33 may be supplemented, primarily in the part of the spectrum that the human lens filters out with age, so that the output spectrum of the luminaire matches the desired spectrum as much as possible each time. When several red and blue light-emitting diodes are used, each of these light-emitting diodes has its own emitted peak, selected in the above-defined areas of the red or blue part of the spectrum, as in this way it is possible to more precisely adjust the output spectrum to the desired spectrum. The term “supplementation" of spectra refers to the correction of that part of the output spectrum that needs to be regulated, as it is directly related to the age of the user.

As already mentioned, non-image perception is important, with the peak sensitivity of the photoreceptor for non-image perception being at 480 nm, which is approximately in the same part of the spectrum as the emitted peak of the blue light-emitting diode. With the user’s age, the transmittance of the human lens in the blue part of the spectrum decreases significantly more than in green, yellow and red spectra, so the spectra of both primary light- emitting diodes must be adjusted so that the output spectrum of the luminaire is adapted to the user's age and not only to the daylight at a given moment. This means that, for example, for older users, the output spectrum of the luminaire needs to be adjusted by adding part of the spectrum of blue light, i.e. to enrich the spectrum of the light emitted by the luminaire in the blue part of the wavelengths.

The control of the light-emitting diodes is performed via the external control unit 4 which regulates the intensity of an individual light-emitting diode 33-38 via a multi-channel power supply 2, so that it regulates the supply current of each light-emitting diode 33-38. When several different light-emitting diodes of the same type are supplied on the same channel, for example several different blue light-emitting diodes, each with its own power characteristic, and requiring different power supply currents, appropriate current limiters are used to ensure correct current on each light-emitting diode.

Preferably, the power supply 2 has four channels, with one channel for supplying the warm white light-emitting diodes 34, one channel for supplying the cool white light-emitting diodes 33, one channel for supplying the blue light-emitting diodes 35, 37 and one channel for supplying the red light-emitting diodes 36, 38. Using a four-channel power supply 2, the intensity of each channel and thus the power supply current of each light-emitting diode can be changed independently, thus enabling a very precise setting of the output spectrum of the luminaire.

The connection between the light-emitting diodes 33-38, the current limiters and via connection connectors 32 with the power supply 2 can be formed as a printed circuit 31.

At least one diode of each type is combined in a basic LED module 3, wherein the luminaire according to the invention includes at least one basic LED module 3. One controller 4 controls either one basic LED module 3 or, in the case where the luminaire includes several basic LED modules 3, one controller 4 controls all basic LED modules 3. Figure 2 shows a comparison between the desired spectrum and the output spectrum for users of different ages for the warm white solution, i. e. when mimicking the solar spectrum at CCT of 2700 K, with the dashed line representing the desired spectrum and the solid line representing the output spectrum of the luminaire.

Figure 3 shows a comparison between the desired spectrum and the output spectrum for users of different ages for the cool white solution, i. e. when mimicking the solar spectrum at CCT of 6500 K, with the dashed line representing the desired spectrum and the solid line representing the output spectrum of the luminaire.

The matching of both spectra (“goodness of fit”) is evaluated with the value of R², which is a value between 0.0 and 1.0 and has no unit. A higher value of R² means a greater match of the two curves (spectra). Using the spectrally adjustable luminaire according to the invention, the output spectrum of the luminaire according to the invention matches the desired spectrum at a value of R² of at least 0.7 for a warm white solution and at a value of R² of at least 0.5 for a cool white solution.

In one embodiment, when the corresponding power supply currents in the memory locations are predetermined according to the pre-set desired spectra, predetermined power supply currents for each individual diode are entered in each memory location of the memory unit, which are determined by the direct matching method between the desired spectrum and the emitted spectra in a way that the output spectrum of the luminaire matches the desired spectrum at a value of R² of at least 0.7 for a warm white solution and at a value of R² of at least 0.5 for a cool white solution.

In one of the embodiments, when the corresponding intensities of the power supply currents in the memory locations are determined at a given moment according to the pre-set desired spectra and the actual light in the room, the luminaire according to the invention additionally includes various types of sensors 5 that are connected to the control unit 4, such as a sensor for sensing the light intensity in the room, a sensor for sensing the light spectrum inside and outside of the room, and so on. The actual light spectrum in the room transmitted to the control unit 4 by the sensor 5 is the result of the sum of the light with the output spectrum emitted by the luminaire according to the invention and the light from other light sources, e.g. other luminaires or daylight that penetrates the room. In this case, the control unit 4 further includes a process unit 43, wherein a control programme module is implemented on the control unit 4, which, by using a suitable algorithm that includes the direct matching method between the actual light spectrum in the room and the desired spectrum, determines the real-time intensities of the power supply currents of individual light-emitting diodes, in that the actual spectrum corresponds to the desired spectrum at a value of R² of at least 0.7 for the warm white solution and at a value of R² of at least 0.5 for the cool white solution. Thus, the luminaire can automatically maintain light in the room, which largely follows the desired spectrum, regardless of changes in external lighting conditions, which are for instance the result of other luminaires or daylight that penetrates the room.

The spectrally adjustable luminaire according to the invention can be controlled manually, for example via switches, a suitable display or via a suitable application installed on a mobile device, which ensures great flexibility and applicability of such a system. The spectrally adjustable luminaire according to the invention can be controlled automatically, for example, that the output spectrum is determined depending on the time and the pre-set programme to follow the spectrum of natural daylight depending on the user’s age. The spectrally adjustable luminaire can also be controlled by a combination of manual and automatic control, which allows the user to manually select the output spectrum regardless of the pre set programme.

Embodiment

A spectrally adjustable luminaire consists of a housing 10 terminated on one side by a light diffuser 12, and in the housing 10 there is a power supply 2 for light-emitting diodes, an LED parabola 11 and four basic LED modules 3, each of the modules 3 including a printed circuit 31, on which light-emitting diodes 33-38 and the connection connectors 32 for connection to the power supply 2 are located. Externally to the housing, there is a control unit 4 including a controller 41 for controlling the light-emitting diodes 33-38 via the power supply 2, and a memory unit 42. The controller 41 is preferably a DALI controller.

One basic LED module 3 includes six light-emitting diodes, namely one warm white light- emitting diode 34 with a colour temperature of 2700 K, one cool white light-emitting diode 33 with a colour temperature of 5000 K, two blue light-emitting diodes 35, 37, the first blue light-emitting diode 35 having an emitted peak at 430 nm, the second blue light-emitting diode 37 at 480 nm, and two red light-emitting diodes 36, 38, the first red light-emitting diode 36 having an emitted peak at 650 nm and the second red light-emitting diode 38 at 730 nm.

The power supply 2 has four channels, with one channel for supplying the warm white light- emitting diode 34, one channel for supplying the cool white light-emitting diode 33, one channel for supplying the blue light-emitting diodes 35, 37 and one channel for supplying the red light-emitting diodes 36, 38. As two different blue light-emitting diodes or two red light-emitting diodes are supplied on the same channel, said diodes each having its own power supply characteristic, and requiring different supply currents, appropriate current limiters are used to ensure correct current on each light-emitting diode, said limiters being integrated in the printed circuit 31.

In the memory unit 42, data on the desired spectra and the corresponding power supply currents for controlling the individual light-emitting diodes 33-38 are stored at the memory locations to achieve output spectra that are as similar as possible to the desired spectra. The intensities of the power supply currents at the memory locations are pre-determined according to the pre-set desired spectra in a way that the output spectrum of the luminaire matches the desired spectrum at a value of R² of at least 0.7 for a warm white solution and at a value of R² of at least 0.5 for a cool white solution, the value of R² being determined by the method of direct matching of both spectra.

The user selects the desired spectrum via a display, for example the user wants to mimic daylight for a specific age group.

Then, the controller 41 , depending on the selected desired spectrum based on the data of the corresponding power supply currents for controlling the individual light-emitting diodes 33-38 stored in the memory unit 42, controls the power supply 2 to supply the light-emitting diodes 33-38 in a way that the output spectrum of the luminaire matches the desired spectrum at a value of R² of at least 0.7 for a warm white solution and at a value of R² of at least 0.5 for a cool white solution.

Claims

1. A spectrally adjustable luminaire that mimics daylight and takes into account the age of the user, characterized by including:

- at least one warm white light-emitting diode (34), at least one cool white light-emitting diode (33), at least one blue light-emitting diode (35, 37) and at least one red light-emitting diode (36, 38);

- a power supply (2) for supplying the light-emitting diodes (33-38), and

- a control unit (4) including at least a controller (41) for controlling the light-emitting diodes (33-38) via the power supply (2), and a memory unit (42), the memory unit (42) including a plurality of memory locations for storing data on the desired spectra, including the associated intensities of power supply currents for controlling the individual light-emitting diodes (33-38) to achieve the desired spectra, the corresponding intensities of the power supply currents in the memory locations being either predetermined according to the pre-set desired spectra or at a given moment determined according to the pre-set desired spectra and the actual light in the room, wherein the controller (41), depending on the selected spectrum based on the data of the desired spectra stored in the memory unit (42) and the corresponding power supply currents for controlling the individual light-emitting diodes (33-38), controls the power supply (2) for supplying the light-emitting diodes (33-38), the intensity of the power supply current of a particular light-emitting diode (33-38) being determined in a way that the output spectrum of the luminaire matches the desired spectrum at a value of R² of at least 0.7 for a warm white solution and at a value of R² of at least 0.5 for a cool white solution, the value of R² being determined by the method of direct matching of both spectra, and wherein the desired spectrum mimics the spectrum of daylight at a particular part of the day and is simultaneously corrected for the user's age.

2. A spectrally adjustable luminaire according to Claim 1, characterised in that the warm white light-emitting diode (34) has a colour temperature of 2700 K and the cool white light- emitting diode (33) has a colour temperature of 5000 K.

3. A spectrally adjustable luminaire according to Claims 1 and 2, characterized in that the red light-emitting diodes (36, 38) emit light in the red part of the spectrum in the range between 650 nm to 730 nm, the blue light-emitting diodes (35, 37) emit light in the blue part of the spectrum in the range between 420 nm to 480 nm.

4. A spectrally adjustable luminaire according to preceding claims, characterized by including one warm white light-emitting diode (34) with a colour temperature of 2700 K, one cool white light-emitting diode (33) with a colour temperature of 5000 K, two blue light- emitting diodes (35, 37), one blue light-emitting diode having an emitted peak at 420 nm, and the other at 480 nm, and two red light-emitting diodes (36, 38), one red light-emitting diode having an emitted peak at 650 nm and the other at 730 nm.

5. A spectrally adjustable luminaire according to preceding claims, characterized in that the power supply (2) has four channels, with one channel for supplying the warm white light- emitting diode (34), one channel for supplying the cool white light-emitting diode (33), one channel for supplying the blue light-emitting diodes (35, 37) and one channel for supplying the red light-emitting diodes (36, 38).

6. A spectrally adjustable luminaire according to Claim 6, characterized in that, when several different light-emitting diodes of the same type are supplied on the same channel, current limiters are used to ensure correct current on each light-emitting diode.

7. A spectrally adjustable luminaire according to preceding claims, characterized in that the control unit (4) additionally includes a process unit (43), wherein a control programme module is implemented on the control unit (4), and at least one sensor (5) for detecting the actual spectrum of the current light in the room is connected to the control unit (4), the actual light spectrum in the room being the result of the sum of the light with the output spectrum emitted by the luminaire and the light from other light sources or daylight that penetrates the room, wherein the control programme module, by using a suitable algorithm that includes the direct matching method between the actual light spectrum in the room and the desired spectrum, determines the real-time intensities of the power supply currents of individual light-emitting diodes (33-38), in that the actual spectrum corresponds to the desired spectrum at a value of R² of at least 0.7 for the warm white solution and at a value of R² of at least 0.5 for the cool white solution.