Hold times for lighting devices

Abstract

A method of controlling a plurality of lighting devices of a lighting system is disclosed. The plurality of lighting devices comprising a first lighting device comprising a first memory and a second lighting device comprising a second memory. The method comprises: obtaining a light scene for the plurality of lighting devices, the light scene comprising a first light setting associated with the first lighting device and a second light setting associated with the second lighting device, the second light setting being different from the first light setting, determining a first hold time for the first lighting device based on one or more first lighting characteristics of the first light setting, determining a second hold time, different from the first hold time, for the second lighting device based on one or more second lighting characteristics of the second light setting, controlling the first lighting device according to the first light setting of the light scene and the second lighting device according to the second light setting of the light scene, controlling, after the first hold time, the first lighting device by dimming the light output of the first lighting device to a first target light setting, and controlling, after the second hold time, the second lighting device by dimming the light output of the second lighting device to a second target light setting.

Description

[0001] Hold times for lighting devices

[0002] FIELD OF THE INVENTION

[0003] The invention relates to a method of controlling a plurality of lighting devices of a lighting system and a computer program product for performing the method. The invention further relates to a control system controlling a plurality of lighting devices of a lighting system.

[0004] BACKGROUND

[0005] Presence sensors allow to optimize energy usage by automatically switching on the lighting devices when presence is detected and switching off the lighting devices when presence is no longer detected. The period for keeping a lighting device on after the last presence (e.g. motion) has been detected, is known as the hold time. A user or a system operator typically sets the hold time for a lighting device or a group of lighting devices manually, such that the lighting device or the group of lighting devices switch off or dim to a target level if no presence has been detected after the hold time expires. The hold time for a non-transitional area (e.g. a living room, an office, etc.) is typically longer compared to the hold time of a transitional area (e.g. a hallway). For instance, the hold time for a lighting device located in a hallway may be set to 5 minutes, and the hold time for a lighting device in an office environment may be set to 15 or even 30 minutes. It may, however, occur that a user has left the area already, which would result in that the lighting devices in the area remain on and thereby unnecessarily consume energy. Another problem that may occur is that when the user is still present in the area, the lights are switched off because the presence of the user is not detected (e.g. due to a lack of movement of the user).

[0006] WO 2015054611 Al discloses intelligent lighting systems which include lighting fixtures communicatively coupled to processors and memory to provide efficient, highly responsive, and custom-tailored lighting to meet the needs and preferences of a given user or application. Configuration profiles along with identification sensing provide objectspecific and person-specific lighting conditions within intelligent lighting system environments. Rules may be keyed to detection of the object or person within the illuminated area and can be based on identifying information about the object or person and location data acquired by sensors.

[0007] SUMMARY OF THE INVENTION

[0008] It is an object of the invention to improve the hold times for multiple lighting devices to reduce energy consumption without switching off the light.

[0009] According to a first aspect, the object is achieved by method of controlling a plurality of lighting devices of a lighting system comprising a first lighting device comprising a first memory and a second lighting device comprising a second memory, the method comprising: obtaining a light scene for the plurality of lighting devices, the light scene comprising a first light setting associated with the first lighting device and a second light setting associated with the second lighting device, the second light setting being different from the first light setting, determining a first hold time for the first lighting device based on one or more first lighting characteristics of the first light setting, determining a second hold time, different from the first hold time, for the second lighting device based on one or more second lighting characteristics of the second light setting, controlling the first lighting device according to the first light setting of the light scene and the second lighting device according to the second light setting of the light scene, controlling, after the first hold time, the first lighting device by dimming the light output of the first lighting device to a first target light setting, and controlling, after the second hold time, the second lighting device by dimming the light output of the second lighting device to a second target light setting.

[0010] Current (home) lighting systems are controlled according to light scenes. These light scenes define different light settings having different lighting characteristics (such as colors, saturation and brightness values). These light settings are typically associated with respective lighting devices, such that when the light scene is activated, the respective lighting devices are controlled accordingly. The inventors have realized that different light settings of a light scene have a different effect on the area, and that by setting different hold times for different lighting devices, not all lighting devices are switched off at the same time. The different hold times are determined based on lighting characteristics of respective light settings. Consequently, when the light scene is activated, the plurality of lighting devices are switched on, and they are dimmed (or switched off) after a period of time that is determined dependent on the characteristics of the light settings associated with the respective lighting devices. This is beneficial, because it contributes to reduce the energy consumption without completely switching off all lighting devices and leaving a user in the dark.

[0011] The method may further comprise: determining, based on the one or more first lighting characteristics and / or based of the one or more second lighting characteristics, if the first and second light settings are decorative or functional light settings, and wherein the first and / or second hold times are determined based on whether the respective light scene is a decorative or a functional light setting. The one or more first lighting characteristics may be indicative of that the first light setting is a decorative light setting, and the one or more second lighting characteristics may be indicative of that the second light setting is a functional light setting. The first and second hold times may be determined such that the lighting device associated with the functional light setting has a hold time longer than the decorative light setting. Alternatively, the first and second hold times may be determined such that the lighting device associated with the decorative light setting has a hold time longer than the functional light setting. The lighting system may comprise one or more memories configured to information indicating whether a light setting is a decorative or a functional light setting. It is beneficial to discriminate between functional and decorative (ambient) light settings, because it may be desirable that lighting devices associated with decorative light settings are dimmed before lighting devices associated with functional light settings (e.g. when the user is working at his or her desk and functional task lighting may be more important than (remote) decorative lighting), or it may be desirable that lighting devices associated with functional light settings are dimmed before lighting devices associated with decorative light settings (e.g. when the user is watching a movie, decorative (dimmed) lighting may be more important than functional lighting).

[0012] The first and / or second hold time may be further determined based on whether the light scene is a functional or a decorative light scene. The method may further comprise: obtaining light scene information indicating if the light scene is a decorative light scene or a functional light scene, and if the light scene is a decorative light scene, and if the first light setting is a decorative setting and the second light setting is a functional light setting, determining the first and second hold times such that the first hold time is longer than the second hold time, and if the light scene is a functional light scene, and if the first light setting is a functional light setting and the second light setting is a decorative light setting, determining the first and second hold times such that the first hold time is longer than the second hold time. The inventors have realized that light scenes may perform a certain function. For instance, an office light scene may be defined as a functional light scene while a candlelight light scene may be defined as a decorative light scene. It is therefore beneficial to take the function of the light scene into account. The lighting system may comprise one or more memories configured to information indicating whether a light scene is a decorative or a functional light setting.

[0013] The method may further comprise: communicating the first hold time to the first lighting device, storing the first hold time in the first memory of the first lighting device, communicating the second hold time to the second lighting device, storing the second hold time in the second memory of the second lighting device. This enables the lighting devices to dim to the respective target light settings after the respective hold times expire. This is beneficial because no additional command needs to be sent to the lighting devices when the hold times expire. The first and second hold times may, for example, be communicated to the respective lighting devices by a (local or remote) control system.

[0014] The method may further comprise: communicating the light scene to the first lighting device, storing the light scene in the first memory of the first lighting device, communicating the light scene to the second lighting device, and storing the light scene in the second memory of the second lighting device. In other words, the complete light scene (including the light settings for other lighting devices) may be stored in the memories of the plurality of lighting devices. This provides flexibility, because the lighting device may be controlled according to different light settings under different circumstances. This may further enable the lighting devices to provide dynamic light effects by transitioning between light settings of the light scene over time. The first and second light scenes may, for example, be communicated to the respective lighting devices by a central (local or remote) control system.

[0015] The step of controlling the first lighting device according to the first light setting may comprises: selecting, by the first lighting device, the first light setting from the light scene based on an association between the first lighting device and the first light setting, and initiating the first hold time. The step of controlling the second lighting device according to the second light setting comprises: selecting, by the second lighting device, the second light setting from the light scene based on an association between the second lighting device and the second light setting, and initiating the second hold time. This is beneficial, because it enables the lighting system to control the lighting devices by sending a single command to the lighting devices to activate the scene (and therewith the respective light settings) and to activate the hold times.

[0016] The first hold time and the second hold time may be stored as part of the light scene. Thus, when the light scene is communicated to the lighting devices, the respective hold times are also sent. The hold times may be associated with the respective light settings (as defined by the light scene), which are then applied to the respective associated lighting devices. This is beneficial, because it provides flexibility, because the lighting device may be controlled according to different light settings of a respective light scene under different circumstances.

[0017] The method may further comprise: obtaining type information indicative of the types of the first and second lighting devices. The first hold time may be determined further based on a first type of the first lighting device, and the second hold time may be determined further based on a second type of the second lighting device, the second type of the second lighting device being different from the first type of the first lighting device. The hold times may thus be determined based on the types of the respective lighting devices. For instance, light strips may be assigned shorter hold times compared to bulbs or spotlights.

[0018] The method may further comprise: obtaining location information indicative of the locations of the first and second lighting devices. The first hold time may be determined further based on a first location of the first lighting device, and the second hold time may be determined further based on a second location of the second lighting device. The hold times may thus be determined based on the locations of the respective lighting devices. For instance, lighting devices in transitional areas (i.e. areas wherein users typically move) may be assigned shorter hold times compared to lighting devices in non-transitional areas (i.e. areas wherein users typically stay for a time longer than in transitional areas). In another example, lighting devices located centrally in an area may be assigned longer hold times compared to lighting devices located in the periphery of the area.

[0019] The step of dimming the light output of the first lighting device to the first target light setting may comprise: dimming the light output of the first lighting device to the first target light over a first transition period, and the second hold time may be determined such that it expires after the transition period. This way, lighting in the area is gradually dimmed. Additionally, the step of dimming the light output of the second lighting device to the second target light setting may comprise: dimming the light output of the second lighting device to the second target light over a second transition period.

[0020] The first and / or the second target light settings may be off light settings. Alternatively, it may be dimmed light settings with a lower brightness compared to the respective light settings. Additionally or alternatively, first and / or the second target light settings may be first dimmed light settings with a lower brightness compared to the respective light settings, and subsequently be off light settings.

[0021] The method may further comprise: receiving an input signal indicative of a presence of a subject, and controlling the first lighting device according to the first light setting of the light scene and the second lighting device according to the second light setting of the light scene upon receiving the input signal. The lighting devices are thus controlled when the subject (the user) is present, and the respective hold times are initiated when the presence of the subject has been detected, for instance by a presence sensor.

[0022] According to a second aspect, the object is achieved by one or more computer program products for one or more computing devices, the one or more computer program products comprising computer program code to perform any of the above-mentioned methods when the one or more computer program products are run on respective processing units of the respective computing devices.

[0023] According to a third aspect, the object is achieved by a control system for controlling a plurality of lighting devices of a lighting system comprising a first lighting device comprising a first memory and a second lighting device comprising a second memory, wherein the control system comprises one or more processors configured to: obtain a light scene, the light scene comprising a first light setting associated with the first lighting device and a second light setting associated with the second lighting device, the second light setting being different from the first light setting, determine a first hold time for the first lighting device based on one or more first lighting characteristics of the first light setting, determine a second hold time, different from the first hold time, for the second lighting device based on one or more second lighting characteristics of the second light setting, control the first lighting device according to the first light setting of the light scene and the second lighting device according to the second light setting of the light scene, control, after the first hold time, the first lighting device by dimming the light output of the first lighting device to a first target light setting, and control, after the second hold time, the second lighting device by dimming the light output of the second lighting device to a second target light setting.

[0024] It should be understood that the computer program product(s) and the control system may have similar and / or identical embodiments and advantages as the above- mentioned lighting devices.

[0025] BRIEF DESCRIPTION OF THE DRAWINGS

[0026] 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:

[0027] Fig. 1 shows schematically an example of a lighting system comprising a plurality of lighting devices and a control system for controlling the plurality of lighting devices;

[0028] Figs. 2a-c shows schematically examples of hold times; and

[0029] Fig. 3 shows schematically a method of controlling a plurality of lighting devices of a lighting system.

[0030] 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.

[0031] DETAILED DESCRIPTION

[0032] Fig. 1 shows schematically an example of a lighting system 100 comprising a plurality of lighting devices 110, 112 and a control system 102 for controlling the plurality of lighting devices 110, 112. The control system 102 may be any type or device or system configured to control lighting devices 110, 112. 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 control system 102 may be selected based on the system architecture of the lighting system 100.

[0033] The lighting devices 110, 112 may, for example, be controlled by the processor 106 of the control system 102, by a central lighting control system (e.g. a bridge, a gateway, etc.), by another connected device, etc. The control system 102 may comprise a communication unit 104. The lighting devices 110, 112 may comprise similar communication units (not shown) configured to receive lighting control signals. The communication units may comprise hardware for communicating via one or more wireless communication protocols, for example Bluetooth, Wi-Fi, Li-Fi, 3G, 4G, 5G or ZigBee. A specific communication technology may be selected based on the system architecture of the lighting system. The lighting devices 110, 120 may be any type of lighting device comprising one or more (LED) light sources, and a processing unit for controlling the light output (e.g. hue, saturation and / or brightness) of the one or more light sources based on received control signals. The lighting devices 110, 112 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 control system 102). A lighting control signal may comprise lighting control instructions for controlling the light output, such as the color, intensity and saturation of the one or more light sources. The lighting devices 110, 120 may be arranged for providing general lighting, such as functional lighting or decorative lighting. The lighting devices 110, 112 may be light bulbs, light strips, TLEDs, light tiles, etc. The lighting devices 110, 112 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 110, 112 may have different maximum / minimum dimming capabilities and / or different maximum / minimum brightness levels.

[0034] The control system comprises one or more processors 106. The control system may comprise one processor, which may be comprised in a single device (e.g. a mobile device, a hub, a bridge, a lighting control system, etc.). Alternatively, the system may comprise a plurality of processors 106 which may be distributed across different devices (e.g. in a central control device (such as a mobile device, a hub, a bridge, a lighting control system, etc.), in the cloud, in the lighting devices 110, 112, etc. The processors 106 may be configured to perform different tasks. The distribution of the processors 106 and their tasks may be dependent on the system architecture of the lighting system.

[0035] The one or more processors 106 are configured to obtain the light scene, the light scene comprising a first light setting associated with the first lighting device 110 and a second light setting associated with the second lighting device 112, the second light setting being different from the first light setting, determine a first hold time for the first lighting device 110 based on one or more first lighting characteristics of the first light setting, determine a second hold time, different from the first hold time, for the second lighting device 112 based on one or more second lighting characteristics of the second light setting, control the first lighting device 110 according to the first light setting of the light scene and the second lighting device 112 according to the second light setting of the light scene, control, after the first hold time, the first lighting device by dimming the light output of the first lighting device 110 to a first target light setting, and control, after the second hold time, the second lighting device 112 by dimming the light output of the second lighting device 112 to a second target light setting. Figs. 2a-2c illustrate examples of hold times. In these figures, the first light setting Isl has been assigned a first hold time tl based on one or more first lighting characteristics of the first light setting, and second light setting ls2 has been assigned a second hold time t2 based on one or more second lighting characteristics of the second light setting. The vertical axis of the graph may, for example, be the intensity of the light settings. It should be understood that the intensity is merely an example, and that other characteristics of the light settings may be used for determining the hold times and adjusted after the hold time expires. In the example of Fig. 2a, the light output of the lighting devices are dimmed over time after the hold times expire. In the example of Fig. 2b, the lighting devices are dimmed to 0 immediately. In the example of Fig. 2c, the second hold time t2 expires after the light output of the first lighting device has been dimmed. In other examples, the hold time may comprise multiple dimming steps, for example a first dimming step to a lower first intensity (e.g. 50%) and the intensity of the light output may remain at that lower first intensity for a predefined period of time (e.g. 10 seconds), and a second dimming step to 0 after the predefined period of time. The dimming curves may be linear, exponential, etc.

[0036] In an example, (one of) the one or more processors 106 may obtain the light scene from a memory 108 of the control system. The memory 108 may store different light scenes, which may be activated based on different inputs (e.g. sensor inputs, user activations, lighting control routines, etc.). The light scene defines a first light setting for a first lighting device 110 of the lighting system 100, and a second light setting for a second lighting device 112 of the lighting system 100. The light scene may be defined as a look-up table storing associations between light settings and lighting devices. The light settings comprise lighting characteristics such as color, intensity, brightness, beam angle / shape, level of dynamics, etc. The one or more processors 106 are further configured to analyze the lighting characteristics for determining hold times based on the lighting characteristics. The one or more processors 106 are configured to determine a first hold time for the first lighting device 110 based on one or more first lighting characteristics of the first light setting, and determine a second hold time for the second lighting device 112 based on one or more second lighting characteristics of the second light setting. The one or more processors 106 may, for example, access a memory storing associations between lighting characteristics and target hold times. For example, the one or more lighting characteristics of a light setting may indicate that the light setting has a certain color (e.g. red), a certain saturation (e.g. 100%), and a certain brightness (e.g. 50% or a lumen value) with no dynamics (light output changes over time). The hold time may be determined based on these values. For instance, the one or more processors 106 may start with a default hold time (e.g. 5 minutes, 10 minutes, 30 minutes) and adjust the default hold time based on the lighting characteristics to determine the hold time. The one or more processors 106 may, for example, determine to adjust the default hold time based on a specific color (e.g. red results in a reduction of the hold time), to further adjust the default hold time based on the brightness (e.g. a 50% brightness decreases the hold time by 50%), to further adjust the hold time based on the saturation (e.g. a 100% saturation decreases the hold time by 75%), to further adjust the hold time based on a level of dynamics (a higher level of dynamics may result in an increase of the hold time). In another example, the one or more processors 106 may, for example, determine the hold time for a light setting based on the position of the light setting with respect to the BBL (black body locus) (e.g. the lower the CCT, the lower the hold time), or based on a distance of the light setting with respect to the BBL (the further away from the BBL, the lower the hold time). In another example, the one or more processors 106 may determine the hold time based on a single lighting characteristic, for instance the brightness (the lower the brightness, the lower the hold time). It should be noted that these are mere examples of determining the hold time, and that the skilled person is able to design alternatives without departing from the scope of the appended claims.

[0037] The one or more processors 106 are further configured to control the plurality of lighting devices 110, 112 based on respective light settings of the light scene. For example, the one or more processors 106 may be comprised in a lighting control device (e.g. a bridge, a mobile device, a remote cloud server, etc.), and may be configured communicate the respective light settings to the respective lighting devices of the lighting system 100. Alternatively, the light scene and / or respective light settings may already be stored in the memories of the (respective) lighting devices, and the one or more processors 106 may be configured to send a light scene recall command and / or a light setting recall command to the lighting devices, whereupon the lighting devices activate the respective light settings.

[0038] The first and second hold times may be initiated when the light scene is activated. The light scene may be activated based on a trigger of a presence sensor of the lighting system (e.g. a camera, a PIR sensor, an RF presence sensor, etc.). Alternatively the light scene may be activated based on a user input (e.g. a selection of the light scene via a user interface, a toggle of a switch, etc.), be activated based on a lighting control routine, be activated based on another sensor input (e.g. a temperature sensor, a daylight sensor, etc.). It should be understood that these are mere examples of activations of the light scene, and that the skilled person is able to design alternatives without departing from the scope of the appended claims.

[0039] The one or more processors 106 are further configured to control the first and second lighting devices 110, 112 after the respective first and second hold times by dimming the light output to respective first and second target light settings. For example, the one or more processors 106 may be comprised in a lighting control device (e.g. a bridge, a mobile device, a remote cloud server, etc.), and may be configured communicate the respective target light settings to the respective lighting devices of the lighting system 100, whereupon the respective lighting devices may dim to the respective target light settings. Alternatively, the hold times and the light scene and / or respective target light settings may already be stored in the memories of the (respective) lighting devices, and the one or more processors 106 may be configured to send a light scene recall command and / or a target light setting recall command to the lighting devices, whereupon the lighting devices dim to the respective target light settings. Alternatively, one or more processors comprised in the first and second lighting devices 110, 112 may initiate timers when the first and second hold times are initiated, and dim from the respective light settings to the respective target light settings.

[0040] The one or more processors 106 may be configured to communicate the first hold time to the first lighting device 110. The first lighting device 110 may receive the first hold time and store the first hold time in the first memory of the first lighting device 110. The one or more processors 106 may be further configured to communicate the second hold time to the second lighting device 112. The second lighting device 112 may receive the second hold time and store the second hold time in the second memory of the second lighting device 110. The first and second lighting devices 110, 112 may be configured to dim to the respective target light settings after the respective hold times expire.

[0041] The one or more processors 106 may be further configured to communicate (e.g. via a communication unit via a (wireless) network) the light scene to the first lighting device, and the first lighting device may store the light scene in the first memory of the first lighting device. Additionally, the one or more processors 106 may be configured to communicate (e.g. via a communication unit via a (wireless) network) the light scene to the second lighting device, and the second lighting device may store the light scene in the second memory of the second lighting device. The one or more processors 106 may control the first lighting device according to the first light setting of the light scene and the second lighting device according to the second light setting of the light scene by communicating a scene recall command (e.g. individual messages or a broadcast message) to the first and second lighting devices. The first and second lighting devices may receive the recall command and select, respectively, the first light setting and the second light setting from, respectively, the first memory and the second memory and control the respective light outputs based on the respective light settings. The first lighting device 110 may select the first light setting from the light scene based on an association between the first lighting device 110 and the first light setting (stored in the first memory), and initiate the first hold time upon activation of the first light setting. Similarly, the second lighting device 112 may select the second light setting from the light scene based on an association between the second lighting device 112 and the second light setting (stored in the second memory), and initiate the second hold time upon activation of the second light setting. The associations may be stored as lookup tables in the respective memories.

[0042] The first hold time and the second hold time may be stored as part of the light scene. The hold times may be associated with the respective light settings (as defined by the light scene), which light scene may be stored in the memories of the lighting devices 110, 112. The respective first and second hold times may then be applied by processing units of the respective lighting devices upon activation of the light scene.

[0043] The dimming from the light settings to the respective target light settings may be transitions from the light settings to the respective target light settings, and may occur over a predefined period of time. Alternatively, the dimming may be instant (see Fig. 2b). The first and / or the second target light settings may be off light settings (see Figs. 2a-2c). Alternatively, the light settings may be dimmed light settings with a lower brightness compared to the respective light settings. The target light settings are such that the power consumption of the respective lighting devices is reduced.

[0044] The one or more processors 106 (e.g. comprised in the first lighting device or in a central lighting controller) may be further configured to dim the light output of the first lighting device to the first target light over a first transition period during the first transition period. The one or more processors 106 may be further configured to determine the second hold time such that the second hold time expires after the first transition period. This is illustrated in Fig. 2c. The one or more processors 106 (e.g. comprised in the second lighting device or in a central lighting controller) may dim the light output of the second lighting device to the second target light setting by dimming the light output of the second lighting device to the second target light over a second transition period (as shown in Fig. 2c).

[0045] The first and second hold times may expire if no user presence has been determined / detected during the respective hold time. The user presence may be detected by a presence sensor of the lighting system (e.g. a camera, a PIR sensor, an RF presence sensor, etc.).

[0046] The one or more processors 106 may be further configured to determine the first and second hold times based on functions of the different light settings of the light scene. The one or more processors may analyze the lighting characteristics of the first and second light settings. The one or more processors may, for example, determine, based on the one or more first lighting characteristics and / or based of the one or more second lighting characteristics, if the first and second light settings are decorative or functional light settings. The first and / or second hold times may be determined based on whether the respective light scene is a decorative or a functional light setting. Functional light settings may be defined as light settings with a lower saturation and / or a higher brightness compared to decorative light settings. Functional light settings may, for example, be white light, while decorative light settings may be colored light. The light scene may comprise both of these types of light settings. The one or more first lighting characteristics may be indicative of that the first light setting is a decorative light setting, and the one or more second lighting characteristics may be indicative of that the second light setting is a functional light setting. The first and second hold times may be determined such that the lighting device associated with the functional light setting has a hold time longer than the decorative light setting. Alternatively, the first and second hold times may be determined such that the lighting device associated with the decorative light setting has a hold time longer than the functional light setting. It may be desirable that a lighting device associated with a decorative light setting is dimmed before a lighting device associated with a functional light setting (e.g. when the user is working at his or her desk and functional task lighting may be more important than (remote) decorative lighting), or it may be desirable that a lighting device associated with a functional light setting is dimmed before a lighting device associated with a decorative light setting (e.g. when the user is watching a movie, decorative (dimmed) lighting may be more important than functional lighting).

[0047] Additionally, the one or more processors 106 may be configured to determine the first and second hold times based on a function of the light scene. The one or more processors 106 may, for example, obtain light scene information indicating if the light scene is a decorative light scene or a functional light scene. The light scene information may, for example, be obtained from a memory, from a user via a user interface or be obtained by analyzing the light settings of the light scene. The light scene information may be a descriptor of the light scene indicating the function of the light scene. For instance, an “office” light scene can be considered a functional light scene, while a “candle light” or an “entertainment” light scene can be considered a decorative light scene. Additionally or alternatively, the descriptor may simply indicate if the light scene is “decorative” or “functional”. The one or more processors 106 may be further configured to, if the light scene is a decorative light scene, and if the first light setting is a decorative setting and the second light setting is a functional light setting, determine the first and second hold times such that the first hold time is longer than the second hold time. Additionally, if the light scene is a functional light scene, and if the first light setting is a functional light setting and the second light setting is a decorative light setting, the one or more processors may determine the first and second hold times such that the first hold time is longer than the second hold time.

[0048] The one or more processors 106 may be further configured to obtain type information indicative of the types of the first and second lighting devices. The type information may be obtained from a (local or remote) memory, received from a lighting control system, received from the lighting devices 110, 112, etc. The one or more processors 106 may be further configured to determine the first hold time further based on a first type of the first lighting device, and the second hold time further based on a second type of the second lighting device, the second type of the second lighting device being different from the first type of the first lighting device. For instance, lighting devices arranged to provide decorative lighting (e.g. colored lighting) may be assigned shorter hold times compared to lighting devices arranged for providing functional lighting (e.g. task lighting). For instance, light strips may be assigned shorter hold times compared to spotlights or office lighting.

[0049] The one or more processors 106 may be further configured to obtain location information indicative of the locations of the first and second lighting devices. The location of the first and second lighting devices may be predefined. The predefined location (and, optionally, the orientation of the first and second lighting devices) may, for example, have been defined by a user. The user may have provided information about a predefined / frequently used location (and / or orientation) of the first and second lighting devices on a map of the space. In another example, the predefined / frequently used location may be derived from the map of the space (e.g. form a building information model, a user- created map, etc.). Alternatively, the location (and the orientation) of the first and second lighting devices may be obtained by detecting a current location (and orientation) of the first and second lighting devices. The system may also monitor the locations and / or orientations of the first and second lighting devices over time, and determine a typical or frequent location and / or orientation of the first and second lighting devices based on the monitoring. The locations and / or the orientations may, for example, be detected by an (indoor) positioning system, for instance based on signal characteristics of signals transmitted between the first and second lighting device. Additionally, the method may further comprise: repeatedly detecting the current location and / or orientation of the camera, and remapping the plurality of light settings onto the plurality of lighting units if a difference between a new locations and / or orientations of the first and second lighting devices and a previous locations and / or orientations of the first and second lighting devices exceeds a threshold. Additionally or alternatively, the processor 106 may be configured to obtain the location information, for example, 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 optionally other devices in the space. The location information may be indicative of coordinates of the first and second lighting devices relative to the space. Additionally, the location information may be indicative of the orientation of the first and second lighting devices relative to the space. The orientation may for example be based on data from an orientation sensor comprised in the first and second lighting devices, based on a predetermined orientation of the camera (e.g. defined by a user via a user interface), etc. Such techniques of obtaining location and / or orientation information are known in the art and will therefore not be discussed in further detail.

[0050] The one or more processors 106 may be further configured to determine the first hold time further based on a first location of the first lighting device, and the second hold time further based on a second location of the second lighting device. The hold times may thus be determined based on the locations of the respective lighting devices. For instance, lighting devices in transitional areas (hallways) may be assigned shorter hold times compared to lighting devices in non-transitional areas (offices, living rooms, etc.).

[0051] Additionally or alternatively, the one or more processors 106 may be further configured to determine the first hold time further based on a first orientation of the first lighting device, and the second hold time further based on a second orientation of the second lighting device. The hold times may thus be determined based on the orientations of the respective lighting devices. For instance, lighting devices oriented upwards may be assigned shorter hold times compared to lighting devices oriented downwards.

[0052] Fig. 3 illustrates steps of a method 300 of controlling a plurality of lighting devices of a lighting system, the plurality of lighting devices comprising a first lighting device comprising a first memory and a second lighting device comprising a second memory. The method 300 comprises: obtaining 302 a light scene for the plurality of lighting devices, the light scene comprising a first light setting associated with the first lighting device and a second light setting associated with the second lighting device, the second light setting being different from the first light setting, determining 304 a first hold time for the first lighting device based on one or more first lighting characteristics of the first light setting, determining 306 a second hold time, different from the first hold time, for the second lighting device based on one or more second lighting characteristics of the second light setting, controlling 308 the first lighting device according to the first light setting of the light scene and the second lighting device according to the second light setting of the light scene, controlling 310, after the first hold time, the first lighting device by dimming the light output of the first lighting device to a first target light setting, and controlling 312, after the second hold time, the second lighting device by dimming the light output of the second lighting device to a second target light setting.

[0053] The method 300 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 one or more processors 106 of the control system 102.

[0054] 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.

[0055] 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’.

[0056] 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 (300) of controlling a plurality of lighting devices of a lighting system, the plurality of lighting devices comprising a first lighting device comprising a first memory and a second lighting device comprising a second memory, the method (300) comprising: obtaining (302) a light scene for the plurality of lighting devices, the light scene comprising a first light setting (Is 1) associated with the first lighting device and a second light setting (ls2) associated with the second lighting device, the second light setting being different from the first light setting, determining (304) a first hold time (tl) for the first lighting device based on one or more first lighting characteristics of the first light setting, determining (306) a second hold time (t2), different from the first hold time, for the second lighting device based on one or more second lighting characteristics of the second light setting, controlling (308) the first lighting device according to the first light setting of the light scene and the second lighting device according to the second light setting of the light scene, controlling (310), after the first hold time, the first lighting device by dimming the light output of the first lighting device to a first target light setting, and controlling (312), after the second hold time, the second lighting device by dimming the light output of the second lighting device to a second target light setting.

2. The method (300) of claim 1, wherein the method (300) further comprises: determining, based on the one or more first lighting characteristics and / or based of the one or more second lighting characteristics, if the first and second light settings are decorative or functional light settings, and wherein the first and / or second hold times are determined based on whether the respective light scene is a decorative or a functional light setting.

3. The method (300) of claim 2, further comprising:obtaining light scene information indicating if the light scene is a decorative light scene or a functional light scene, and if the light scene is a decorative light scene, and if the first light setting is a decorative setting and the second light setting is a functional light setting, determining the first and second hold times such that the first hold time is longer than the second hold time, and if the light scene is a functional light scene, and if the first light setting is a functional light setting and the second light setting is a decorative light setting, determining the first and second hold times such that the first hold time is longer than the second hold time.

4. The method (300) of any preceding claim, further comprising: communicating the first hold time to the first lighting device, storing the first hold time in the first memory of the first lighting device, communicating the second hold time to the second lighting device, storing the second hold time in the second memory of the second lighting device.

5. The method (300) of any preceding claim, further comprising: communicating the light scene to the first lighting device, storing the light scene in the first memory of the first lighting device, communicating the light scene to the second lighting device, and storing the light scene in the second memory of the second lighting device.

6. The method (300) of claim 4 or 5, wherein the step of controlling the first lighting device according to the first light setting comprises: selecting, by the first lighting device, the first light setting from the light scene based on an association between the first lighting device and the first light setting, and initiating the first hold time, and wherein the step of controlling the second lighting device according to the second light setting comprises: selecting, by the second lighting device, the second light setting from the light scene based on an association between the second lighting device and the second light setting, and initiating the second hold time.

7. The method (300) of claim 4, 5 or 6, wherein the first hold time and the second hold time are stored as part of the light scene.

8. The method (300) of any preceding claim, wherein the method (300) further comprises: obtaining type information indicative of the types of the first and second lighting devices, wherein the first hold time is determined further based on a first type of the first lighting device, and wherein the second hold time is determined further based on a second type of the second lighting device, the second type of the second lighting device being different from the first type of the first lighting device.

9. The method (300) of any preceding claim, wherein the method (300) further comprises: obtaining location information indicative of the locations of the first and second lighting devices, wherein the first hold time is determined further based on a first location of the first lighting device, and wherein the second hold time is determined further based on a second location of the second lighting device.

10. The method (300) of any preceding claim, wherein the step of dimming the light output of the first lighting device to the first target light setting comprises: dimming the light output of the first lighting device to the first target light over a first transition period, wherein the second hold time is determined such that it expires after the first transition period.

11. The method (300) of claim 10, wherein the step of dimming the light output of the second lighting device to the second target light setting comprises: dimming the light output of the second lighting device to the second target light over a second transition period.

12. The method (300) of any preceding claim, wherein the first and / or the second target light setting are off light settings.

13. The method (300) of any preceding claim, further comprising: receiving an input signal indicative of a presence of a subject, and controlling the first lighting device according to the first light setting of the light scene and the second lighting device according to the second light setting of the light scene upon receiving the input signal.

14. A computer program product for a computing device, the computer program product comprising computer program code to perform the method (300) of any preceding claim when the computer program product is run on a processing unit of the computing device.

15. A control system (102) for controlling a plurality of lighting devices (110,112) of a lighting system (100), the plurality of lighting devices comprising a first lighting device (110) comprising a first memory and a second lighting device (112) comprising a second memory, wherein the control system (102) comprises one or more processors configured (106) to: obtain a light scene, the light scene comprising a first light setting (Isl) associated with the first lighting device (110) and a second light setting (ls2) associated with the second lighting device (112), the second light setting being different from the first light setting, determine a first hold time (tl) for the first lighting device based on one or more first lighting characteristics of the first light setting, determine a second hold time (t2), different from the first hold time, for the second lighting device based on one or more second lighting characteristics of the second light setting, control the first lighting device according to the first light setting of the light scene and the second lighting device according to the second light setting of the light scene, control, after the first hold time, the first lighting device by dimming the light output of the first lighting device to a first target light setting, andcontrol, after the second hold time, the second lighting device by dimming the light output of the second lighting device to a second target light setting.

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