WO2024056354A1

WO2024056354A1 - A method of controlling lighting devices according to a dimming profile

Info

Publication number: WO2024056354A1
Application number: PCT/EP2023/073484
Authority: WO
Inventors: Dzmitry Viktorovich Aliakseyeu; Jérôme Eduard MAES; Jan EKKEL
Original assignee: Signify Holding B.V.
Priority date: 2022-09-16
Filing date: 2023-08-28
Publication date: 2024-03-21

Abstract

A method of controlling a plurality of lighting devices in an environment according to a dimming profile over a period of time is disclosed. The dimming profile defines a transition from an initial illumination with an initial target brightness and an initial target color or color temperature to a subsequent illumination comprising a subsequent target brightness and a subsequent target color or color temperature. The plurality of lighting devices are different lighting devices with different light emission properties. The method comprises: obtaining the light emission properties of the plurality of lighting devices, selecting a first lighting device from the plurality of lighting devices which has first light emission properties for providing first illumination that follows the transition defined by dimming profile, controlling, over the period of time, the first lighting device based on the dimming profile to provide the first illumination in the environment, selecting a second lighting device from the plurality of lighting devices which has second light emission properties for providing second illumination that follows the dimming profile for only a part of the transition defined by dimming profile, and controlling, over a part of the period of time that corresponds to the part of the transition, the second lighting device to provide the second illumination in the environment.

Description

A method of controlling lighting devices according to a dimming profile

FIELD OF THE INVENTION

The invention relates to a method of controlling a plurality of lighting devices in an environment according to a dimming profile over a period of time, and to a computer program product for executing the method. The invention further relates to a controller for controlling a plurality of lighting devices in an environment according to a dimming profile over a period of time.

BACKGROUND

Home environments typically contain multiple controllable lighting devices for creation of atmosphere, accent or task lighting. These controllable lighting devices may be controlled via a user interface of a control device, such as a smartphone, via a wireless network. A user may select a light scene via the user interface of the control device, whereupon the lighting devices are controlled according to light settings defined by the light scene. Alternatively, the light scene may be activated automatically (e.g. based on a scheduled lighting control routine, based on a sensor that has been triggered, etc.).

If a lower light intensity level is required, for instance for wake-up or fall- asleep lighting routines, deep dimming of the light output of the lighting devices may be required. The dim level is then adjusted over a period of time. Additionally, the color or the color temperature of the light emitted by the lighting devices is adjusted over the period of time, for instance to mimic the changing color temperature of daylight.

SUMMARY OF THE INVENTION

The inventors have realized that when a lighting system comprises different types of lighting devices, not all lighting devices may be able to provide the intended illumination. For instance, some lighting devices may be configured to provide white light only (e.g. with a fixed color temperature), other lighting devices may be configured to provide white light with different color temperatures, while other lighting devices may be configured to provide colored light. Furthermore, these different lighting devices may have different dimming ranges and/or different brightness ranges (lumen). Such a plurality of different lighting devices may be controlled based on a lighting control routine, for instance a wake-up lighting routine. The wake-up lighting routine may be defined as a dimming profile that indicates a transition from an initial illumination to one or more subsequent illuminations. Consequently, all lighting devices are controlled according to that dimming profile, resulting in that all lighting devices start the transition by providing light that approximates the dimming profile. The inventors have realized that this control may not always have the desired effect on the lighting atmosphere in the environment wherein the lighting system is installed, because some lighting devices are not able to provide illumination with the desired color, color temperature and/or brightness. It is therefore an object to provide a lighting system that improves the accuracy of illumination transitions.

According to a first aspect, the object is achieved by a method of controlling a plurality of lighting devices in an environment according to a dimming profile over a period of time, wherein the dimming profile defines a transition from an initial illumination with an initial target brightness and an initial target color or color temperature to a subsequent illumination comprising a subsequent target brightness and a subsequent target color or color temperature, wherein the plurality of lighting devices are different lighting devices with different light emission properties, the method comprising: obtaining the light emission properties of the plurality of lighting devices, selecting a first lighting device from the plurality of lighting devices which has first light emission properties for providing first illumination that follows the transition defined by dimming profile, controlling, over the period of time, the first lighting device based on the dimming profile to provide the first illumination in the environment, selecting a second lighting device from the plurality of lighting devices which has second light emission properties for providing second illumination that follows the dimming profile for only a part of the transition defined by dimming profile, wherein the second light emission properties are such that the second lighting device is able to provide the subsequent target color or color temperature and unable to provide the initial target color or color temperature, or wherein the second light emission properties are such that the second lighting device is able to provide the initial target color or color temperature and unable to provide the subsequent target color or color temperature, and controlling, over a part of the period of time that corresponds to the part of the transition, the second lighting device to provide the second illumination in the environment. The dimming profile defines a transition from an initial illumination to a subsequent illumination. The dimming profile may, for example, be (part of) a lighting control routine or be (part of) a dynamic light scene. The first lighting device is selected from the plurality of lighting devices based on its light emission properties, wherein the first lighting device has light emission properties for providing illumination that (substantially) follows the transition (from the initial illumination to the subsequent illumination) as defined by dimming profile. The second lighting device is a lighting device that, due to its light emission properties, is unable to provide the illumination of the full transition. The second lighting device is therefore selected based on its light emission characteristics and controlled only during the part of the transition for which it is able to follow the dimming profile. As a result, the second lighting device participates in the lighting control routine or the dynamic light effect only during a part thereof. This is beneficial, because the accuracy of the target illumination transition from the initial illumination to the subsequent illumination is improved.

The initial target color temperature and the initial target brightness may be lower than the subsequent target color temperature and the subsequent target brightness, respectively. The dimming profile may, for example, be a wake-up lighting routine, wherein the brightness and the color temperature increase over the period of time. The second lighting device may then participate in the wake-up lighting routine only when its light emission properties are such that the second lighting device can provide illumination which follows the dimming profile.

The initial target color temperature and the initial target brightness may be higher than the subsequent target color temperature and the subsequent target brightness, respectively. The dimming profile may, for example, be a fall-asleep lighting routine, wherein the brightness and the color temperature decrease over the period of time. The second lighting device may then participate in the fall-asleep lighting routine only when its light emission properties are such that the second lighting device can provide illumination which follows the dimming profile.

The dimming profile may be a profile that follows a circadian rhythm lighting cycle. The dimming profile may be a dynamic light scene that changes throughout the day and follows a natural daylight curve to support the circadian rhythm of a person. The second lighting device (and optionally further second lighting devices) may be selected and controlled at one or more moments throughout the day to provide illumination that follows the dimming profile. The method may further comprise: obtaining location information indicative of a first location of the first lighting device and a second location of the second lighting device relative to the user or relative to the environment, respectively, and the first lighting device may be selected further based on the first location of the first lighting device relative to a user or relative to the environment, respectively. Additionally or alternatively, the second lighting device may be selected further based on the second location of the second lighting device relative to the user and/or relative to the environment. This way, the lighting devices can be selected such that they are distributed in a particular way in the environment, for instance to achieve an evenly lit environment in accordance with the dimming profile or to achieve a particular region of the environment being illuminated.

The step of obtaining the light emission properties of the plurality of lighting devices may comprise: receiving a plurality of identifiers of the plurality of lighting devices, and obtaining the light emission properties of the plurality of lighting devices based on the respective identifiers. Additionally or alternatively, the step of obtaining the light emission properties of the plurality of lighting devices may comprise: receiving, via a user interface, one or more user inputs indicative of the light emission properties of the plurality of lighting devices.

The method may further comprise: receiving a specification of environmental factors causing a discrepancy between intrinsic first and/or second light emission properties and a perceived first and/or second light emission properties, and determining the first and/or second light emission properties of the respective first and/or second lighting device, respectively, by adjusting the intrinsic first and/or second light emission properties, respectively, based on the received specification of the environmental factors. Environmental factors that may influence the perceived light emission properties of a lighting device include a natural light source in the vicinity of the lighting device, a reflective surface in the vicinity of the lighting device, (partial) shading of the lighting device, e.g. by a lamp shade, by an interior element in which the lighting device is integrated such as a cove and so on. By compensating for such environmental factors, the determined light emission properties of a lighting device more closely resemble its perceived light emission properties, thereby further improving the accuracy of the generation of the desired illumination.

The method may further comprise: receiving type information indicative of the types of the first and second lighting devices, and adjusting the dimming profile based on the types of the first and second lighting devices. Different types of lighting devices may have different illumination effects on the environment. For instance, a light bulb provides a different (spatial) illumination effect compared to a spotlight, a light strip or a wall-washer. To provide correct illumination of the environment (according to the dimming profile) it is beneficial to adjust the dimming profile based on the types of the lighting devices.

The step of selecting the second lighting device may comprise selecting the second lighting device such that a combined illumination of the first and second illumination follows the dimming profile during the part of the period of time. This is beneficial, because the combined light output of both the first and the second lighting device together follow the dimming profile during the part of the period of time.

The second lighting device may have a fixed light brightness and a fixed color temperature, and the method may comprise: switching the second lighting device on during the part of the period of time that corresponds to the part of the transition. The second lighting device may be a lighting device of which the light output cannot be controlled, besides switching the lighting device on or off.

The method may further comprise: receiving an input indicative of an ambient light level in the environment, and adjusting the dimming profile based on the ambient light level, wherein the first and second lighting devices are selected and controlled based on the adjusted dimming profile. Taking into account the ambient light level in the environment may be beneficial, because it improves the accuracy of the generation of the target illumination according to the dimming profile.

According to a second aspect, the object is achieved by a computer program product for a computing device, the computer program product comprising computer program code to perform any of the above-mentioned methods when the computer program product is run on a processing unit of the computing device.

According to a third aspect, the object is achieved by a controller for controlling a plurality of lighting devices in an environment according to a dimming profile over a period of time, wherein the dimming profile defines a transition from an initial illumination with an initial target brightness and an initial target color or color temperature to a subsequent illumination comprising a subsequent target brightness and a subsequent target color or color temperature, wherein the plurality of lighting devices are different lighting devices with different light emission properties, the controller comprising: an input interface configured to obtain the light emission properties of the plurality of lighting devices, a processor configured to select a first lighting device from the plurality of lighting devices which has first light emission properties for providing first illumination that follows the transition defined by dimming profile, control, over the period of time, the first lighting device based on the dimming profile to provide the first illumination in the environment, select a second lighting device from the plurality of lighting devices which has second light emission properties for providing second illumination that follows the dimming profile for only a part of the transition defined by dimming profile, wherein the second light emission properties are such that the second lighting device is able to provide the subsequent target color or color temperature and unable to provide the initial target color or color temperature, or wherein the second light emission properties are such that the second lighting device is able to provide the initial target color or color temperature and unable to provide the subsequent target color or color temperature, and control, over a part of the period of time that corresponds to the part of the transition, the second lighting device to provide the second illumination in the environment. It should be understood that the controller and the computer program product may have similar and/or identical embodiments and advantages as the above-mentioned methods.

BRIEF DESCRIPTION OF THE DRAWINGS

The above, as well as additional objects, features and advantages of the disclosed systems, devices and methods will be better understood through the following illustrative and non-limiting detailed description of embodiments of devices and methods, with reference to the appended drawings, in which:

Fig. 1 shows schematically an example of a lighting system comprising two lighting devices and a controller for controlling the lighting devices in an environment according to a dimming profile over a period of time;

Figs. 2a and 2b show schematically examples of dimming profiles;

Fig. 3 shows schematically an example of a lighting system comprising a plurality of lighting devices; and

Fig. 4 shows schematically a method of controlling a plurality of lighting devices in an environment according to a dimming profile over a period of time.

All the figures are schematic, not necessarily to scale, and generally only show parts which are necessary in order to elucidate the invention, wherein other parts may be omitted or merely suggested. DETAILED DESCRIPTION

Fig. 1 shows an example of a lighting system 100 comprising two lighting devices 112, 114 and a controller 102 for controlling the lighting devices 112, 114 according to a dimming profile over a period of time. The controller 102 may be any type or device or system configured to control lighting device 112, 114. The controller 102 may, for example, be comprised in a smartphone, a central lighting control system (e.g. a bridge, a home lighting controller), in a lighting device, in the cloud, etc. The location of the controller 102 may be selected based on the system architecture of the lighting system 100.

The lighting devices 112, 114 have different light emission properties. The lighting devices 112, 114 may be different types of lighting devices. For instance, a lighting device may be configured to provide white light only (e.g. with a fixed color temperature), while another lighting device may be configured to provide white light with different color temperatures (or to provide colored light). Furthermore, these different lighting devices 112, 114 may have different maximum/minimum dimming capabilities and/or different maximum/minimum brightness levels. The lighting devices 112, 114 comprise one or more (LED) light sources. The lighting devices 112, 114 may be light bulbs, light strips, TLEDs, light tiles, etc. The lighting devices 112, 114 may comprise a control unit, such as a microcontroller (not shown), for controlling the light output generated by the one or more light sources based on received lighting control signals (which may be received from the controller 102). A lighting control signal may comprise lighting control instructions for controlling the light output, such as the color, intensity and saturation the one or more light sources.

The dimming profile defines a transition from an initial illumination with an initial target brightness and an initial target color or color temperature to a subsequent illumination comprising a subsequent target brightness and a subsequent target color or color temperature. Figs. 2a and 2b illustrate examples of dimming profiles (curves) with the intensity i on the horizontal axis and the color temperature ct on the vertical axis. The transition over the period of time may for instance start at the origin. The dimming profile may be linear or non-linear. Fig. 2a illustrates two dimming profiles: a first profile (solid line) wherein both the intensity and the color temperature increase over the period of time and a second profile (dotted line) wherein both the intensity and the color temperature decrease over the period of time. Fig. 2b illustrates a dimming profile wherein both the intensity and the color temperature increase over the period of time. It should be understood that these dimming profiles are mere examples, and that the skilled person is able to design alternatives without departing from the scope of the appended claims. For instance, the dimming profile may define a decrease of the intensity and an increase the color temperature over the period of time (or vice versa). In another example, the color may change over the period of time (as compared to the color temperature). The color may, for example, change according to the colors of the rainbow, or transition between a set of predefined colors. The colors may be defined as a light scene (e.g. a predefined light scene, a user light scene, etc.). The light scene may define a plurality of light settings according to which the plurality of lighting devices 112, 114 are to be controlled over the period of time. The transition may be a dynamic light scene (of which the illumination changes over the period of time), or the transition may be a part of the dynamic light scene. The dimming profile shown in Figs. 2a and 2b may be a generic dimming profile that defines the target illumination for the environment. Based on this generic dimming profile, individual dimming profiles may be generated by the processor 106 for the individual first and second lighting devices 112, 114. The individual dimming profiles may be further based on the types of lighting devices, the light emission properties, the locations of the lighting devices, etc.

The controller 102 comprises an input interface 104 configured to obtain the light emission properties of the plurality of lighting devices 112, 114. The input interface may be a receiver, or be part of a transceiver, configured to receive the light emission properties via a (wireless) network. The light emission properties may be received directly from the plurality of lighting devices 112, 114, or from another device (e.g. a central lighting controller such as a hub, bridge, smartphone, home control system, a cloud server, etc.). Alternatively, the input interface 104 may be an input to the processor 106, and the light emission properties may be obtained from a memory 108, which may be comprised in the controller 102. The input interface 104 may for example be configured to receive a plurality of identifiers of the plurality of lighting devices 112, 114, and obtain the light emission properties of the plurality of lighting devices based on the respective identifiers, which identifiers may be used by the processor 106 to look up the light emission properties of the lighting devices identified by the provided identifier in a data structure such as a lookup table, database or the like in which the respective light emission properties of the plurality of lighting devices identified by respective identifiers are listed. Additionally or alternatively, the input interface 104 may be configured to receive, via a user interface, one or more user inputs indicative of the light emission properties of the plurality of lighting devices. The controller 102 further comprises a processor 106 (e.g. a microcontroller, circuitry, a microchip, etc.). Depending on the system architecture of the lighting system 100, the processor 106 may be distributed across multiple devices. The processor 106 is configured to select a first lighting device from the plurality of lighting devices 112, 114 which has first light emission properties for providing first illumination that follows the (full) transition defined by dimming profile. This has been illustrated in Figs. 2a and 2b, wherein a first lighting device (e.g. first lighting device 112) is selected because it has first light emission properties for providing first illumination that (substantially) follows the full transition 212 (while the second light emission properties of the second lighting device 114 are such that the second lighting device 114 is unable to provide illumination that follows the full transition 212). The processor 106 is further configured to select a second lighting device from the plurality of lighting devices which has second light emission properties for providing second illumination that (substantially) follows the dimming profile for only a part of the transition defined by dimming profile. This has been illustrated in Figs. 2a and 2b, wherein a second lighting device (e.g. second lighting device 114) is selected because it has second light emission properties for providing second illumination that follows the part of the transition 214.

Fig. 2a illustrates two examples of dimming profiles: a first dimming profile indicated by the solid line and a second dimming profile indicated by the dotted line. For the first dimming profile, the initial target color temperature and the initial target brightness are lower than the subsequent target color temperature and the subsequent target brightness, respectively. The first dimming profile may, for example, be a wake-up lighting routine, wherein the brightness and the color temperature increase over the period of time. The second lighting device 114 may be selected by the processor 106, such that the second lighting device 114 participates in the wake-up lighting routine only during the part 214 when its light emission properties are such that the second lighting device 114 can provide illumination which follows the dimming profile for that part 214. For the second dimming profile, the initial target color temperature and the initial target brightness are higher than the subsequent target color temperature and the subsequent target brightness, respectively. The second dimming profile may, for example, be a fall-asleep lighting routine, wherein the brightness and the color temperature decrease over the period of time. The second lighting device 114 may be selected by the processor 106, such that the second lighting device 114 participates in the fall-asleep lighting routine only during the part 214 its light emission properties are such that the second lighting device can provide illumination which follows the dimming profile for that part 214.

The processor 106 is further configured to control, over the period of time 212, the first lighting device 112 based on the dimming profile to provide the first illumination in the environment, and to control, over a part of the period of time that corresponds to the part of the transition 214, the second lighting device to provide the second illumination in the environment. The controller 102 may, for example, comprise a communication unit 110, and the processor 106 may be configured to control the lighting devices via the communication unit 110. The communication unit 110 may be a transmitter or transceiver configured to communicate lighting control signals to the lighting devices 112, 114 to change the light output of the lighting devices 112, 114. The processor 106 may control the first and second lighting devices 112, 114 over the period of time 212 and the part of the period of time 214, respectively, by communicating the lighting control signals to the lighting devices 112, 114 over the (part ol) the period of time. Alternatively, the processor 106 may communicate a command to each lighting device 112, 114 to instruct the respective lighting device to transition from the initial illumination to the subsequent illumination over the (part ol) the period of time.

The dimming profile may be a profile that follows a circadian rhythm lighting cycle. The dimming profile may be a dynamic light scene that changes throughout the day to support the circadian rhythm of a person. The second lighting device (and optionally further second lighting devices) may be selected and controlled only at moments throughout the day at which they are able to provide the required illumination (with a target intensity and/or color or color temperature) that follows the dimming profile.

The processor 106 may be further configured to obtain location information indicative of a first location of the first lighting device and a second location of the second lighting device relative to a user or relative to the environment. The location information may, for example, be received from an (indoor) positioning system (such as an RF-based indoor positioning system or a visible light communication (VLC) based positioning system), it may be based on the signal strength of signals transmitted between one or more lighting devices and the controller 102. The first and second location may be indicative of coordinates of the lighting devices relative to the environment or relative to the user. The first and second locations may be user-defined. A user may, for instance, indicate the locations of the lighting devices on a map using a user interface. Such techniques of obtaining location information are known in the art and will therefore not be discussed in further detail. The processor 106 may be further configured to select the first lighting device from the plurality of lighting devices further based on the first location of the first lighting device relative to a user or relative to the environment, and/or select the second lighting device further based on the second location of the second lighting device relative to the user and/or relative to the environment. If, for example, the lighting system comprises more than two lighting devices, the processor 106 may select the first and/or second lighting devices further based on their positions relative to the user and/or the environment (and based on their light emission properties). Fig. 3 illustrates an example wherein lighting devices 312, 314, 316, 318 are installed in an environment 300. The processor 106 may obtain the light emission properties of the plurality of lighting devices 312, 314, 316, 318 and obtain location information indicative of the locations of the plurality of lighting devices 312, 314, 316, 318 relative to the environment (or relative to the user 320). Lighting devices and 312 and 314 may, for example, comprise light emission properties for providing the first illumination that follows the full transition 212 defined by dimming profile, while lighting devices and 316 and 318 may, for example, comprise light emission properties for providing the second illumination that follows a part of the transition 214 defined by the dimming profile. Instead of controlling all lighting devices 312, 314, 316, 318, the processor 106 may select a first lighting device for providing the first illumination that follows the full transition and a second lighting device for providing the second illumination that follows a part of the transition based on their locations relative to the environment 300 or relative to the user 320. The processor 106 may, for example, select lighting devices 314 and 318 based on the user position if deep dimming levels are required, because these lighting devices are located further away from the user. In another example, when higher lumen levels are required, the processor 106 may, for example, select a ceiling-mounted lighting device instead of a floor lamp.

The location information may be further indicative of the orientation of the lighting devices relative to the environment or relative to the user, and the processor 106 may be further configured to select the first lighting device from the plurality of lighting devices further based on the orientation of the first lighting device relative to a user or relative to the environment, and/or select the second lighting device further based on the orientation of the second lighting device relative to the user and/or relative to the environment. The processor 106 may, for example, select a lighting device directed away from the user if deep dimming levels are required. In another example, when certain color/saturation levels are required, the processor 106 may select a lamp directed towards a wall instead of a ceiling-mounted lamp directed towards the floor. The processor 106 may be configured to receive a specification of environmental factors causing a discrepancy between intrinsic first and/or second light emission properties and a perceived first and/or second light emission properties, and determine the first and/or second light emission properties of the respective first and/or second lighting device by adjusting the intrinsic first and/or second light emission properties based on the received specification of the environmental factors. An environmental factor may be a factor that causes a discrepancy between the intrinsic light emission properties of a lighting device and its perceived light emission properties. For example, a lighting device may be positioned in the vicinity of a reflective surface, a natural light source, etc., which may cause the luminous output of the lighting device to be perceived as being brighter due to the reflected or natural light adding to the perceived brightness of the lighting device. As another example, the lighting device may be partially obscured, may be covered by a lampshade or the like, or may be aimed away from an observer such that the light intensity perceived by an observer of the lighting device may be higher than the actual light intensity produced with the lighting device. It should be understood that these are examples of such environmental factors, and that the skilled person will be able to design alternatives without departing from the scope of the appended claims. To compensate for such a discrepancy, the processor 106 may enter a light emission properties determination mode. The processor 106 may determine the intrinsic light emission properties of the selected lighting device, which may be achieved as explained above, e.g. by communication between the lighting device and the controller 102. Next, the processor 106 may determine the one or more environmental factors that cause the discrepancy between the intrinsic dim capability and the perceived dim capability of the lighting device. The processor 106 10 may be made aware of such environmental factors in any suitable manner. For example, information regarding such environmental factors may be entered into the lighting system 100, i.e. the controller 102, e.g. using a user interface, for each lighting device during configuration of the lighting system 100. For example, a user’s smart device operable as a user interface may be used to acquire such information using the smart device’s camera either during a configuration session of the lighting system 100 or at the moment creation of the light scene having a desired dimming or fading effect is desired. Alternatively, the environmental factors may be sensed either by one or more sensors embedded in a lighting device and communicatively coupled to the controller 102 or by cameras communicatively coupled to the controller 102 and present in the room in which the lighting system 1 is installed. Upon determining the environmental factors in, the processor 106 may adjust the intrinsic light emission of the lighting device based on the determined environmental factors to determine the actual (perceived) light emission of the lighting device. This may be repeated for each lighting device of the plurality of lighting devices 112, 114.

Additionally or alternatively, the processor 106 may, for example, be configured to receive an input indicative of an ambient light level in the environment, and adjust the dimming profile based on the ambient light level, wherein the first and second lighting devices are selected and controlled based on the adjusted dimming profile. So instead of (or in addition to) taking the intrinsic light emission properties into account, the processor 106 may adjust the diming profile. The processor 106 may, for example, adjust the color or color temperature of the dimming profile based on the color of the ambient light, or adjust the intensity of the dimming profile based on the intensity of the ambient light.

The processor 106 may be configured to select the second lighting device 114 such that a combined illumination of the first and second illumination (of the first and second lighting device) follows the dimming profile during the part of the period of time. The combined light output of both the first and the second lighting device together follow the dimming profile during the part of the period of time. The processor 106 may be further configured to, during (a part ol) the part of the period of time 214, compensate for the additional illumination provided by the second lighting device 114 by, for example, adjusting the brightness and/or the color or color temperature of the light emission of the first lighting device 112 during that (a part ol) the part of the period of time 214.

The second lighting device has a fixed light brightness and a fixed color temperature. In other words, the light output of the second lighting device 114 may be fixed, and the lighting device may be switched on or off by the controller 102. The processor 106 may be configured to switch the second lighting device on during the part of the period of time that corresponds to the part of the transition. This has been illustrated in Fig. 2b, wherein the second lighting device may be a lighting device that has a fixed light brightness and a fixed color temperature, which is only switched on for a part 214 of the transition wherein the light emission of the second lighting device 114 (substantially) follows the dimming profile.

Fig. 4 shows schematically a method 400 of controlling a plurality of lighting devices in an environment according to a dimming profile over a period of time. The dimming profile defines a transition from an initial illumination with an initial target brightness and an initial target color or color temperature to a subsequent illumination comprising a subsequent target brightness and a subsequent target color or color temperature, wherein the plurality of lighting devices are different lighting devices with different light emission properties. The method comprises: obtaining 402 the light emission properties of the plurality of lighting devices, selecting a first lighting device from the plurality of lighting devices which has first light emission properties for providing first illumination that follows the transition defined by dimming profile, controlling, over the period of time, the first lighting device based on the dimming profile to provide the first illumination in the environment, selecting a second lighting device from the plurality of lighting devices which has second light emission properties for providing second illumination that follows the dimming profile for only a part of the transition defined by dimming profile, and controlling, over a part of the period of time that corresponds to the part of the transition, the second lighting device to provide the second illumination in the environment.

The method 400 may be executed by computer program code of a computer program product when the computer program product is run on a processing unit of a computing device, such as the processor 106 of the controller 102.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims.

In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb "comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer or processing unit. In the device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Aspects of the invention may be implemented in a computer program product, which may be a collection of computer program instructions stored on a computer readable storage device which may be executed by a computer. The instructions of the present invention may be in any interpretable or executable code mechanism, including but not limited to scripts, interpretable programs, dynamic link libraries (DLLs) or Java classes. The instructions can be provided as complete executable programs, partial executable programs, as modifications to existing programs (e.g. updates) or extensions for existing programs (e.g. plugins). Moreover, parts of the processing of the present invention may be distributed over multiple computers or processors or even the ‘cloud’. Storage media suitable for storing computer program instructions include all forms of nonvolatile memory, including but not limited to EPROM, EEPROM and flash memory devices, magnetic disks such as the internal and external hard disk drives, removable disks and CD-ROM disks. The computer program product may be distributed on such a storage medium, or may be offered for download through HTTP, FTP, email or through a server connected to a network such as the Internet.

Claims

CLAIMS:

1. A method (400) of controlling a plurality of lighting devices in an environment according to a dimming profile over a period of time, wherein the dimming profile defines a transition from an initial illumination with an initial target brightness and an initial target color or color temperature to a subsequent illumination comprising a subsequent target brightness and a subsequent target color or color temperature, wherein the plurality of lighting devices are different lighting devices with different light emission properties, the method (400) comprising: obtaining (402) the light emission properties of the plurality of lighting devices, selecting (404) a first lighting device from the plurality of lighting devices which has first light emission properties for providing first illumination that follows the transition defined by dimming profile, controlling (406), over the period of time, the first lighting device based on the dimming profile to provide the first illumination in the environment, selecting (408) a second lighting device from the plurality of lighting devices which has second light emission properties for providing second illumination that follows the dimming profile for only a part of the transition defined by dimming profile, wherein the second light emission properties are such that the second lighting device is able to provide the subsequent target color or color temperature and unable to provide the initial target color or color temperature, or wherein the second light emission properties are such that the second lighting device is able to provide the initial target color or color temperature and unable to provide the subsequent target color or color temperature, and controlling (410), over a part of the period of time that corresponds to the part of the transition, the second lighting device to provide the second illumination in the environment.

2. The method (400) of claim 1, wherein the dimming profile defines a transition from an initial illumination with an initial target brightness and an initial target color temperature to a subsequent illumination comprising a subsequent target brightness and a subsequent target color temperature, wherein the initial target color temperature and the initial target brightness are lower than the subsequent target color temperature and the subsequent target brightness, respectively.

3. The method (400) of claim 1, wherein the dimming profile defines a transition from an initial illumination with an initial target brightness and an initial target color temperature to a subsequent illumination comprising a subsequent target brightness and a subsequent target color temperature, wherein the initial target color temperature and the initial target brightness are higher than the subsequent target color temperature and the subsequent target brightness, respectively.

4. The method (400) of any preceding claim, wherein the dimming profile is a profile that follows a circadian rhythm lighting cycle.

5. The method (400) of any preceding claim, wherein the method (400) further comprises: obtaining location information indicative of a first location of the first lighting device and a second location of the second lighting device relative to a user or relative to the environment, and wherein the first lighting device is selected further based on the first location of the first lighting device relative to the user or relative to the environment, respectively, and/or wherein the second lighting device is selected further based on the second location of the second lighting device relative to the user and/or relative to the environment, respectively.

6. The method (400) of any preceding claim, wherein the step of obtaining the light emission properties of the plurality of lighting devices comprises: receiving a plurality of identifiers of the plurality of lighting devices, and obtaining the light emission properties of the plurality of lighting devices based on the respective identifiers.

7. The method (400) of any preceding claim, wherein the step of obtaining the light emission properties of the plurality of lighting devices comprises: receiving, via a user interface, one or more user inputs indicative of the light emission properties of the plurality of lighting devices.

8. The method (400) of any preceding claim, further comprising: receiving a specification of environmental factors causing a discrepancy between intrinsic first and/or second light emission properties and a perceived first and/or second light emission properties, and determining the first and/or second light emission properties of the respective first and/or second lighting device, respectively, by adjusting the intrinsic first and/or second light emission properties, respectively, based on the received specification of the environmental factors.

9. The method (400) of any preceding claim, further comprising: receiving type information indicative of the types of the first and second lighting devices, and adjusting the dimming profile based on the types of the first and second lighting devices.

10. The method (400) of any preceding claim, wherein the step of selecting the second lighting device comprises selecting the second lighting device such that a combined illumination of the first and second illumination follows the dimming profile during the part of the period of time.

11. The method (400) of any preceding claim, wherein the second lighting device has a fixed light brightness and a fixed color temperature, and wherein the method (400) comprises: switching the second lighting device on during the part of the period of time that corresponds to the part of the transition.

12. The method (400) of any preceding claim further comprising: receiving an input indicative of an ambient light level in the environment, and adjusting the dimming profile based on the ambient light level, wherein the first and second lighting devices are selected and controlled based on the adjusted dimming profile.

13. A computer program product for a computing device, the computer program product comprising computer program code to perform the method (400) of any preceding claim when the computer program product is run on a processing unit of the computing device.

14. A controller (102) for controlling a plurality of lighting devices (112, 114) in an environment according to a dimming profile over a period of time (212), wherein the dimming profile defines a transition from an initial illumination with an initial target brightness and an initial target color or color temperature to a subsequent illumination comprising a subsequent target brightness and a subsequent target color or color temperature, wherein the plurality of lighting devices (112, 114) are different lighting devices with different light emission properties, the controller (102) comprising: an input interface (104) configured to obtain the light emission properties of the plurality of lighting devices (112, 114), a processor (106) configured to select a first lighting device (112) from the plurality of lighting devices (112, 114) which has first light emission properties for providing first illumination that follows the transition (212) defined by dimming profile, control, over the period of time, the first lighting device (112) based on the dimming profile to provide the first illumination in the environment, select a second lighting device (114) from the plurality of lighting devices (112, 114) which has second light emission properties for providing second illumination that follows the dimming profile for only a part of the transition (214) defined by dimming profile, wherein the second light emission properties are such that the second lighting device is able to provide the subsequent target color or color temperature and unable to provide the initial target color or color temperature, or wherein the second light emission properties are such that the second lighting device is able to provide the initial target color or color temperature and unable to provide the subsequent target color or color temperature, and control, over a part of the period of time that corresponds to the part of the transition (214), the second lighting device (114) to provide the second illumination in the environment.