WO2023110481A1

WO2023110481A1 - Simultaneous control of a functional lighting device based on ambient light level and of a daylight mimicking skylight

Info

Publication number: WO2023110481A1
Application number: PCT/EP2022/084355
Authority: WO
Inventors: Martinus Hermanus Wilhelmus Maria Van Delden; Kevin Thomas WORM; Marcus Cornelis VAN MEEL
Original assignee: Signify Holding B.V.
Priority date: 2021-12-13
Filing date: 2022-12-05
Publication date: 2023-06-22

Abstract

:A system (1) for controlling one or more skylight light sources (43-45,93-95) and one or more functional light sources (46-49) is configured to receive, from a light sensor (51), a signal which is indicative of an ambient light level and determine a functional light level based on the ambient light level, wherein the functional light level reduces when the ambient light level increases. The system is further configured to control the one or more functional light sources according to the functional light level, determine a skylight light level which mimics a daylight light level, and control the one or more skylight light sources according to the skylight light level to mimic daylight while the one or more functional light sources are being controlled according to the functional light level.

Description

Simultaneous control of a functional lighting device based on ambient light level and of a daylight mimicking skylight

FIELD OF THE INVENTION

The invention relates to a system for controlling one or more skylight light sources and one or more functional light sources.

The invention further relates to a method of controlling one or more skylight light sources and one or more functional light sources.

The invention also relates to a computer program product enabling a computer system to perform such a method.

BACKGROUND OF THE INVENTION

In an outdoor environment, the interaction of natural daylight with its ambient environment results in all kinds of light across the sky and vegetation, with the dynamics, patterns, tonalities and intensities of the light being dependent upon geographic location, season, weather and time of day. Frequently, however, humans do not observe this interaction consciously, simply because the constant cycles and variation of nature are an integral part of humans’ natural evolution and habitat. Nevertheless, humans are strongly connected to the emotional and biological benefits of natural light.

In an indoor environment, such as in (deep) open plan offices and hospitality areas, humans’ access to natural light may be limited. For example, because persons are seated too far away from a window or because there is only a small window allowing little light in or because the natural light is diffuse (solar tube, milky glass, fog) or because there is no access to natural light at all. In all these cases, humans become to a greater or lesser extent disconnected from the constant cycles and variation of nature.

In spaces (partially) deprived of natural light, the dynamics that are present in the outdoor environment are missing. Conventional lighting in an indoor environment, such as in an office building, is often static. Control options may be limited to on/off control or control of a dimming level (e.g. allowing dimming up to increase light intensity or dimming down to lower light intensity). Conventional lighting devices are typically arranged in a grid-like structure and controlled individually or as a group in which they are controlled in an identical fashion (e.g. all on/off, all to a specific dimming level or all to a relative dimming level compared to a neighboring lighting device). Generally, the same type of lighting devices is used in a single room or zone. For example, an office space may comprise panel lighting fixtures of the same type in each room except for the corridor where downlights are used. To address different light level needs, the number of lighting devices and/or their placement may be adapted.

Light transmitting structures, such as (real) skylights, (real) windows and the like may be used to increase the amount of daylight that enters an indoor environment. Although light transmitting structures can increase a feeling of well-being of inhabitants of the indoor environment, they are costly and cannot be installed everywhere. Further, they may cause other issues, such as privacy and safety issues.

Artificial skylights have been proposed as a solution. However, it remains important to provide sufficient functional lighting, e.g. to enable employees to work. US 2021/0003260 Al addresses this problem. US 2021/0003260 Al discloses providing light to simulate a natural environment, e.g. imitate light provided by a skylight on a sunny day, while ensuring that the natural lighting remains within general illumination parameters which specify one or more light output characteristics (e.g. hue, saturation, brightness, color temperature) that are suitable for generable illumination of an indoor space. However, the solution of US 2021/0003260 Al makes it difficult to provide energy saving.

SUMMARY OF THE INVENTION

It is a first object of the invention to provide a system, which is able to cause natural lighting to be rendered in agreement with what goes on outdoor while at the same time providing energy saving.

It is a second object of the invention to provide a method, which is able to cause natural lighting to be rendered in agreement with what goes on outdoor while at the same time providing energy saving.

In a first aspect of the invention, a system for controlling one or more skylight light sources and one or more functional light sources comprises at least one input interface, at least one control interface, and at least one processor configured to receive, via said at least one input interface, a signal from a light sensor, said signal being indicative of an ambient light level, determine a functional light level based on said ambient light level, said functional light level being reduced when said ambient light level increases, control, via said at least one control interface, said one or more functional light sources according to said functional light level, determine a skylight light level which mimics a daylight light level, and control, via said at least one control interface, said one or more skylight light sources according to said skylight light level to mimic daylight while said one or more functional light sources are being controlled according to said functional light level.

Unlike conventional lighting systems, in which the light scene is monotonous and static, the light scene of a natural lighting system is dynamic, immersive and time-period dependent. Conventional (time-independent) energy saving means and methods (based on ambient light measurements) have not been applied to a natural lighting system until now, likely because the time-dependent light scene consisting of balanced amounts of functional, biological, and emotional light would be expected to become detuned in this case.

This detuning would be caused by the reduction of the light output of the natural light when measured ambient light levels increase. For example, during a bright and sunny day, the indoor ambient light level may increase well beyond the minimum light level to be sustained at the working surfaces. Thus, to save energy, the natural lighting system throttles down its functional, biological, and emotional light stimuli, for example to the level where there is hardly any light output (i.e. the minimum light output value set in response to the maximum value of the light sensor signal). So, rather than that the emotional light stimuli such as the brightness of the sun and sky portions of the artificial skylight increase, and conformal to the outdoor, the indoor stimuli start to throttle down reflecting the stimuli of the time “night”. Worse, the connection to the outdoor as offered by the artificial skylight and peripheral devices might disappear.

In another example, the sun sets and its slowly getting dark. Hence, the brightness of the light scene gradually increases. However, whereas the outdoor biological and emotional light stimuli are decaying, the indoor light stimuli become stronger and stronger as time progresses, reflected by a brightening skylight. In yet another example, it is getting dark, or it is dark already. Clearly, at this time of day, the functional light level is to throttle up in response to the ambient light level, with the system sustaining the minimum functional light level at the working surface. An artificial skylight also participating therein makes no sense as it is to provide hardly any light at all.

So again, and as holds for each of the above examples, when traditional energy saving means and methods are applied to natural lighting systems, control over at least part of the emotional light stimuli might be lost. Worse, the conveyed light stimuli might almost be the opposite of what should be conveyed.

With the above-described system, the one or more functional light sources, which are separate from the one or more skylight light sources, are controlled to reduce the functional light level when the ambient light level increases, thereby providing energy saving. The one or more skylight light sources are not controlled to reduce the skylight light level when the ambient light level increases, but still mimic daylight such that the artificial skylight remains in agreement with the outdoors. The daylight mimicking is dynamic, thus light output changes over time and thus the skylight output may continue to increase when following the dynamic daylight mimicking program even though the functional light is controlled to be reduced based on the ambient light level.

Said at least one processor may be configured to determine said functional light level such that said functional light level stays above a minimum functional light level and determine said skylight light level such that said skylight light level stays below a maximum skylight light level, wherein said minimum functional light level exceeds said maximum skylight light level.

This measure prevents unstable behavior, e.g. when the skylight light level is also determined based on the ambient light level and the skylight light level is increased when the ambient light level increases. Without such a measure, a reduction in the functional light level might result in an increase in the skylight light level, which might result in a further reduction in the functional light level, which might result in a further increase in the skylight light level, and so forth. As a result, the daylight mimicking would be less accurate. By keeping the maximum skylight light level below the minimum functional light level, this behavior can be avoided.

Said at least one processor may be configured to determine said skylight light level based on said ambient light level, said skylight light level being increased when said ambient light level increases. Alternatively, or additionally, said at least one processor may be configured to determine said skylight light level based on a current time of day. Said at least one processor may be configured to determine said skylight light level further based on a manually configured or automatically determined geographical location.

Said at least one processor may be configured to determine a peripheral light level and control, via said at least one control interface, one or more peripheral light sources according to said peripheral light level while said one or more functional light sources are being controlled according to said functional light level. A peripheral lighting device may be used to enhance the natural lighting, e.g. with a dapple effect.

Said at least one processor may be configured to determine said functional light level such that said functional light level stays above a minimum functional light level and determine said skylight light level and said peripheral light level such that a combination of said skylight light level and said peripheral light level stays below a maximum nonfunctional light level, wherein said minimum functional light level exceeds said maximum non-functional light level. This measure prevents unstable behavior, e.g. when the skylight light level and the peripheral light level are also determined based on the ambient light level and the skylight light level and the peripheral light level are increased when the ambient light level increases. Light contributions from all light sources other than functional light sources to the overall light level at the working surface, are considered non-functional light. The light level of these other light sources, e.g. skylight light sources and peripheral light sources, are together referred to as non-functional light level. The maximum non-functional light level is the light level which the non-functional light level never exceeds.

Said one or more skylight light sources may comprise a first light source representing a sun portion and a second light source representing a sky portion and said at least one processor may be configured to control said first light source according to said skylight light level to mimic daylight. Said at least one processor may be configured to further control said second light source according to said skylight light level. Thus, if the artificial skylight has separate sun and sky portions, at least the sun portion, and optionally the sky portion, mimic daylight.

Said at least one processor may be configured to control said one or more skylight light sources according to said skylight light level between sunrise and sunset. Controlling said one or more skylight light sources to mimic daylight between sunset and sunrise would likely result in unnoticeable or hardly noticeably light (especially when this is done based on measured ambient light levels), which is often not desirable. Said at least one processor may be configured to control said one or more skylight light sources according to a fixed light level between sunset and sunrise.

In a second aspect of the invention, a method of controlling one or more skylight light sources and one or more functional light sources comprises receiving a signal from a light sensor, said signal being indicative of an ambient light level, determining a functional light level based on said ambient light level, said functional light level being reduced when said ambient light level increases, controlling said one or more functional light sources according to said functional light level, determining a skylight light level which mimics a daylight light level, and controlling said one or more skylight light sources according to said skylight light level to mimic daylight while said one or more functional light sources are being controlled according to said functional light level. Said method may be performed by software running on a programmable device. This software may be provided as a computer program product.

Moreover, a computer program for carrying out the methods described herein, as well as a non-transitory computer readable storage-medium storing the computer program are provided. A computer program may, for example, be downloaded by or uploaded to an existing device or be stored upon manufacturing of these systems.

A non-transitory computer-readable storage medium stores at least a first software code portion, the first software code portion, when executed or processed by a computer, being configured to perform executable operation for controlling one or more skylight light sources and one or more functional light sources.

The executable operations comprise receiving a signal from a light sensor, said signal being indicative of an ambient light level, determining a functional light level based on said ambient light level, said functional light level being reduced when said ambient light level increases, controlling said one or more functional light sources according to said functional light level, determining a skylight light level which mimics a daylight light level, and controlling said one or more skylight light sources according to said skylight light level to mimic daylight while said one or more functional light sources are being controlled according to said functional light level.

As will be appreciated by one skilled in the art, aspects of the present invention may be embodied as a device, a method or a computer program product. Accordingly, aspects of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, microcode, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a "circuit", "module" or "system." Functions described in this disclosure may be implemented as an algorithm executed by a processor/microprocessor of a computer. Furthermore, aspects of the present invention may take the form of a computer program product embodied in one or more computer readable medium(s) having computer readable program code embodied, e.g., stored, thereon.

Any combination of one or more computer readable medium(s) may be utilized. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of a computer readable storage medium may include, but are not limited to, the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of the present invention, a computer readable storage medium may be any tangible medium that can contain, or store, a program for use by or in connection with an instruction execution system, apparatus, or device.

A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical (e.g. a visible light communication signal), or any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.

Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber, cable, RF, etc., or any suitable combination of the foregoing. Computer program code for carrying out operations for aspects of the present invention may be written in any combination of one or more programming languages, including an object oriented programming language such as Java(TM), Smalltalk, C++ or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer, or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). Aspects of the present invention are described below with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor, in particular a microprocessor or a central processing unit (CPU), of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer, other programmable data processing apparatus, or other devices create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer readable medium that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the computer readable medium produce an article of manufacture including instructions which implement the function/act specified in the flowchart and/or block diagram block or blocks.

The computer program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

The flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of devices, methods and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the blocks may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustrations, and combinations of blocks in the block diagrams and/or flowchart illustrations, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects of the invention are apparent from and will be further elucidated, by way of example, with reference to the drawings, in which:

Fig. l is a block diagram of a first embodiment of the system;

Fig. 2 shows a schematic representation of the functioning of the system of Fig. 1;

Fig. 3 is a block diagram of a third embodiment of the system;

Fig. 4 is a block diagram of a fourth embodiment of the system;

Fig. 5 shows embodiments of the lighting devices of Fig. 1 installed in a space;

Fig. 6 is a flow diagram of a first embodiment of the method;

Fig. 7 is a flow diagram of a second embodiment of the method;

Fig. 8 illustrates the behavior of a functional light source in a first implementation and the behavior of a skylight light source in an implementation;

Fig. 9 illustrates the behavior of a functional light source in a second implementation and the behavior of the skylight light source of Fig. 8;

Fig. 10 is a flow diagram of a third embodiment of the method;

Fig. 11 is a flow diagram of a fourth embodiment of the method; and

Fig. 12 is a block diagram of an exemplary data processing system for performing the method of the invention.

Corresponding elements in the drawings are denoted by the same reference numeral.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Fig. 1 shows a first embodiment of the system for controlling one or more skylight light sources and one or more functional light sources: a controller 1, e.g. a gateway or a bridge, of a lighting system. The controller 1 comprises a receiver 3, a transmitter 4, a processor 5, and memory 7. In the embodiment of Fig. 1, the lighting system is a natural lighting system comprising a plurality of different pixelated lighting devices that work together as one system, wherein multiple light effects comprising of the different rhythms and cycles of nature are rendered simultaneously by each of a plurality of lighting devices, wherein the multiple light effects are determined based on a (at least partially) predetermined dynamic lighting program which is mapped to a time period by means of a controller, such that the lighting scene changes as time progresses.

Although such a natural lighting system makes it possible to move away from functional illumination to natural light, it is sometimes beneficial to combine functional and natural illumination. Controller 1 of Fig. 1 controls both the functional light sources 46-49 and the skylight light sources 43-45 and 93-95 of the lighting arrangement 31. The skylight light sources 43-45 and 93-95 are embedded in a skylight module of the lighting arrangement 31. . In the example of Fig. 1, the skylight light sources 43-45 of the skylight module are recessed light panels which represent a sky portion and the skylight light sources 93-95 of the skylight module are the one or more portions of the inner side walls of a recess downstream of the skylight light sources 43-45, which represent a sun portion.

Controller 1 controls skylight light sources 43-45 and 93-95 to mimic daylight; light is emitted with a relatively high output level at noon and with a relatively low output level just after sunrise and just before sunset. It would be possible to let the functional light increase with increasing ambient light as well but this makes it difficult to save energy.

The processor 5 of controller 1 is configured to receive, via the receiver 3, a signal from a light sensor 51. The signal is indicative of an ambient light level. The processor 5 is further configured to determine a functional light level based on the ambient light level. The functional light level is reduced when the ambient light level increases. The processor 5 is further configured to control, via the transmitter 4, the functional light sources 46-49 of the lighting arrangement 31 according to the functional light level, determine a skylight light level which mimics a daylight light level, and control, via the transmitter 4, the skylight light sources 93-95, and optionally the skylight light sources 43-45, of the lighting arrangement 31 according to the skylight light level to mimic daylight while the functional light sources 46- 49 are being controlled according to the functional light level.

By reducing the functional light level when the ambient light level increases, energy may be saved. However, reducing the skylight light level when the ambient light level increases is unwanted: the skylight light level should mimic daylight in order to provide the most benefit. The functional light source 19 of a functional lighting device 11 in the same space may be controlled according to the same functional light level as the functional light sources 46-49 or according to a different functional light level.

In the embodiment of Fig. 1, the processor 5 is configured to determine the functional light level such that the functional light level stays above a minimum functional light level and determine the skylight light level such that the skylight light level stays below a maximum skylight light level, wherein the minimum functional light level exceeds the maximum skylight light level.

This measure prevents unstable behavior, e.g. when the processor 5 is configured to determine the skylight light level based on the ambient light level and the skylight light level is increased when the ambient light level increases. Without such a measure, a reduction in the functional light level might result in an increase in the skylight light level, which might result in a further reduction in the functional light level, which might result in a further increase in the skylight light level, and so forth. As a result, the daylight mimicking would be less accurate. By keeping the maximum skylight light level below the minimum functional light level, this behavior can be avoided.

It may not be possible to change the minimum functional light level or the maximum skylight light level. In this case, either the minimum functional light level or the maximum skylight light level may be configured. If it is possible to change the minimum functional light level and the maximum skylight light level, one or both of them may be configured.

Furthermore, the relation between the (controlled) functional light level and the resulting measured ambient light level and/or the relation between the (controlled) skylight light level and the resulting measured ambient light level will likely need to be determined. For example, if it is only possible to change the maximum skylight light level, the functional lighting device may be controlled to emit light at the minimum functional light level and the skylight may be controlled to sweep its light output from its minimum to maximum light output (e.g. within the limits of the pre-programmed light scenes). Alternatively, the functional device may be controlled to emit light at the minimum functional light level and the skylight may be controlled to sweep its light output at different moments.

Based on this sweep, a maximum skylight light level may be determined that corresponds to a lower measured ambient light level than the minimum functional light level. This sweep may be done periodically (e.g. once a day or week or month). For example, after installation of the lighting system, existing functional lights may be removed, been replaced or been added, thereby influencing the calibration settings as set on installation.

Optionally, a peripheral lighting device 57 is present and in this case, the skylight light level and the peripheral light level may be determined such that a combination of the skylight light level and the peripheral light level stays below a maximum non- functional light level. The minimum functional light level exceeds the maximum nonfunctional light level. The peripheral lighting device may be controlled to sweep its light output from its minimum to maximum light output in the manner described above, in the same way as the skylight.

Optionally, the system may be protected from creating non-realistic output with additional safeguards. An additional constraint may be added to the system, e.g. by an installer during installation of the system, to set a minimum ratio between the skylight light level and the functional light level. This should prevent the system from causing undesired light output based on unexpected sensor values.

In the embodiment of Fig. 1, the processor 5 is configured to determine the skylight light level based on the ambient light level, the skylight light level being increased when the ambient light level increases. In an alternative embodiment, the processor 5 is configured to determine the skylight light level based on a current time of day. In this alternative embodiment, the processor 5 may further be configured to determine the skylight light level further based on a manually configured or automatically determined geographical location.

In this alternative embodiment, the control of the skylight may follow a preprogrammed curve/waveform such that the artificial sun (and optionally sky) portions of the skylight are at their brightest at solar noon, with the waveform resembling the shape of that of the natural progress of the daylight intensity. Seasonal dependent times of sunrise and sunset as well as time of year brightness level may be acquired from the Internet server 27 or from another source, for example. In the example of Fig. 1, controller 1 is connected to an Internet access point 21. The Internet access point 21 and the Internet server 27 are connected to the Internet (backbone) 25.

In the embodiment of Fig. 1, a minimum measured light level at a working surface is defined. For example, legislation may require that at least 300 lux is sustained at the working surface at all times. In an alternative embodiment, no minimum measured light at a working surface is defined, e.g. for use in a country that does not require this.

Fig. 2 shows a schematic representation of the functioning of the system of Fig. 1. The light sensor 51 may be located at a working surface or in/at a ceiling above the working surface. If the light sensor is not located at the working surface, the light sensor may be calibrated towards a light meter arranged at the working surface (to meet at least legislation light level). The light sensor 51 receives light from outside the building and light from both the functional light sources and the skylight light sources of light arrangement 31. Preferably, there is no real skylight in the same space.

In the representation of Fig. 2, a side view of the lighting arrangement 31 is depicted. Of the functional light sources 46-49, only light sources 47 and 49 are depicted in Fig. 2. Of the skylight light sources 43-45 representing the sky portion, only light source 43 is depicted in Fig. 2. Of the skylight light sources 93-95 representing the sun portion, only the skylight light source 93 (comprising multiple parts) is depicted in Fig. 2. Frame 97 is the mechanical frame portion of the skylight light source 93. Skylight light sources 94 and 95 have a similar mechanical frame portion (not shown in Fig. 2).

Controller 1 receives a signal from the light sensor 51 indicative of the ambient light level. The functional light level is determined based on the ambient light level and the (desired/required) minimum measured light level. The skylight light level is determined based on the ambient light level. Controller 1 controls the functional light sources according to the functional light level and controls the skylight light sources according to the skylight light level.

The result is that the total light level as measured at the working surface always equals or exceeds the minimum measured light level, e.g. 300 lux. An example of this is shown in Table 1. In this example, the lower threshold limit of the functional light was set at 30 lux.. The contribution of the skylight at the working surface is at most 27.5 lux. The skylight light level is the highest when the ambient light level is the highest.

Table 1

In the embodiment of the controller 1 shown in Fig. 1, the controller 1 comprises one processor 5. In an alternative embodiment, the controller 1 comprises multiple processors. The processor 5 of the controller 1 may be a general-purpose processor, e.g. ARM-based, or an application-specific processor. The processor 5 of the controller 1 may run a Unix-based operating system for example. The memory 7 may comprise one or more memory units. The memory 7 may comprise one or more hard disks and/or solid-state memory, for example.

The receiver 3 and the transmitter 4 may use one or more wired or wireless communication technologies such as Zigbee or Bluetooth to communicate with the light sensor 51 and the lighting arrangement 31 and the peripheral lighting device 57 and Ethernet or Wi-Fi to communicate with the Internet access point 21, for example. In an alternative embodiment, multiple receivers and/or multiple transmitters are used instead of a single receiver and a single transmitter. In the embodiment shown in Fig. 1, a separate receiver and a separate transmitter are used. In an alternative embodiment, the receiver 3 and the transmitter 4 are combined into a transceiver. The lighting arrangement 31 and the peripheral lighting device 57 each comprise one or more LEDs. The LEDs may be direct emitting or phosphor converted LEDs. The lighting arrangement 31 and the peripheral lighting device 57 may comprise one or more luminous surfaces, for example. For example, the lighting arrangement 31 may comprise horizontal luminous surfaces and the peripheral lighting device 57 may comprise one or more vertical luminous surfaces, e.g. to illuminate the office wall.

The controller 1 may comprise other components typical for a controller such as a power connector. The invention may be implemented using a computer program running on one or more processors. In the embodiment of Fig. 1, the system of the invention is a controller. In an alternative embodiment, the system of the invention is a different device, e.g. a lighting device. In the embodiment of Fig. 1, the system of the invention comprises a single device. In an alternative embodiment, the system of the invention comprises a plurality of devices.

Fig. 3 shows a second embodiment of the system for controlling one or more skylight light sources and one or more functional light sources. In the embodiment of Fig. 3 , a single natural lighting arrangement 32 comprises both functional light sources 46-49 and skylight light sources 43-45 and 93-95, like lighting arrangement 31 of Fig. 1. The processor 35 of the lighting arrangement 32 is configured as described in relation to processor 5 of controller 1 of Fig. 1, but is comprised in a lighting arrangement instead of in a separate controller. The processor 35 controls the functional and skylight light sources via an internal control interface 38.

In the embodiment of Fig. 3, the lighting arrangement 32 comprises one processor. The processor 35 of the lighting device 32 generates a drive signal for the functional light sources 46-49 and the skylight light sources 43-45 and 93-95. In an alternative embodiment, the lighting device 32 comprises multiple processors. One of these processors may be a separate (LED) driver, for example. The processor 35 may be an application-specific processor, for example. The processor 35 may be a (very) simple component, for example. The receiver 33 of the lighting arrangement 32 may use one or more wired or wireless communication technologies to receive the signal from the light sensor 51. The memory 37 may comprise solid-state memory, for example.

Fig. 4 shows a third embodiment of the system for controlling one or more skylight light sources and one or more functional light sources: a lighting arrangement 62. Lighting arrangement 62 is similar to lighting arrangement 32 of Fig. 3 but lighting arrangement 62 comprises a processor 65 instead of the processor 35, as shown in Fig. 3. The processor 65 differs from processor 35 in that processor 65 is not configured to determine the skylight light level based on an ambient light level. Instead, the processor 65 is configured to determine the skylight light level based on a current time of day.

The processor 65 may be configured to determine the skylight light level further based on a manually configured or automatically determined geographical location. Seasonal dependent times of sunrise and sunset as well as time of year brightness level may be acquired from the Internet server 27 or from another source, for example.

Fig. 5 shows a perspective view of room in which the lighting arrangement 31 of Fig. 1 has been mounted. In the example of Fig. 5, the lighting arrangement 31 is suspended from a ceiling. In this way, the lighting arrangement looks like a “stand-alone” island. Although an installer is able to place the different light sources of lighting arrangement 31 along an existing suspended ceiling grid in a similar layout as shown in Fig. 1, the experience of an in-grid installation is not as powerful as that of a cluster of light sources coming in the form of an “island”, for example suspended from an open or closed ceiling. This because a grid “puts” an additional raster feel towards the installation.

The lighting arrangement 31 has an island finishing peripheral rim, which is preferably black. By using a height of the artificial skylight that is larger than the height of the island finishing peripheral rim, the level of illusion of the artificial skylight and structural feel of the ceiling may be increased. The functional light sources 46-49 (see Fig. 1) of the lighting arrangement 31 illuminate a table 59 in the room. The functional lighting device 11 is also suspended from the ceiling and illuminates a table 58 in the room. The peripheral lighting device 57 of Fig 1 is suspended from the lighting arrangement 31 and arranged in proximity to at least one of the office walls and illuminates at least one office wall. In an alternative embodiment, the peripheral lighting device 57 is attached to the lighting arrangement 31.

A first embodiment of the method of controlling one or more skylight light sources and one or more functional light sources is shown in Fig. 6. A step 101 comprises receiving a signal from a light sensor which is indicative of an ambient light level. A step 103 comprises determining a functional light level based on the ambient light level as indicated in the signal received in step 101. The functional light level is reduced when the ambient light level increases. A step 105 comprises determining a skylight light level which mimics a daylight light level.

A step 107 comprises controlling the one or more functional light sources and the one or more skylight light sources. Step 107 comprises sub steps 111 and 113. Step 111 comprises controlling the one or more functional light sources according to the functional light level determined in step 103. Step 113 comprises controlling the one or more skylight light sources according to the skylight light level determined in step 105 to mimic daylight while the one or more functional light sources are being controlled according to the functional light level.

A second embodiment of the method of controlling one or more skylight light sources and one or more functional light sources is shown in Fig. 7. The second embodiment of Fig. 7 is an extension of the first embodiment of Fig. 6. In the embodiment of Fig. 7, step 103 is implemented by a step 131 and step 105 is implemented by a step 133. Step 131 comprises determining the functional light level such that the functional light level stays above a minimum functional light level. Step 133 comprises determining the skylight light level such that the skylight light level stays below a maximum skylight light level. The minimum functional light level exceeds the maximum skylight light level.

Fig. 8 illustrates the behavior of a functional light source in a first implementation and the behavior of a skylight light source in an implementation. Fig. 8 shows that the functional light level 71 always exceeds the skylight light level 73. Fig. 8 further shows that the functional light level 71 decreases linearly from the maximum output light level of the functional lighting device to the functional light level defined as minimum as the measured (ambient) light level decreases. Fig. 8 also shows that the skylight light level 73 increases linearly to the maximum skylight light level, which is lower than the minimum functional light level.

Fig. 9 illustrates the behavior of a functional light source in a second implementation and the behavior of the skylight light source of Fig. 9. Fig. 9 shows that the functional light level 81 always exceeds the skylight light level 73. Compared to the behavior of Fig. 8, in Fig. 9, the functional light level 81 decreases from an output light level 85 that corresponds to a desired minimum measured light level, which is lower than maximum output light level of the functional light source, to a minimum functional light level 87. The minimum measured light level may be a legislation light level set at the working surface, e.g. 300 lux. This minimum measured light is sustained at the working surface at all times.

The minimum functional light level 87 has been set by a user. For example, customers may have the option to set a lower control limit beyond which dimming down no longer happens. Compared to the behavior of Fig. 8, in Fig. 9 the functional light level 81 reaches the minimum functional light level at measured light levels below the maximum measured light level. At higher measured light levels (e.g. 80%-100% of the maximum measured light level), the functional light level 81 equals the minimum functional light level 87.

A third embodiment of the method of controlling one or more skylight light sources and one or more functional light sources is shown in Fig. 10. The third embodiment of Fig. 10 is an extension of the first embodiment of Fig. 6. In the embodiment of Fig. 10, step 105 is implemented by steps 151, 153, 155, and 157.

Step 151 comprises determining a current time of day. Step 153 comprises determining whether the current time of day, as determined in step 151, lies between sunrise and sunset. If so, step 155 is performed. If not, step 157 is performed. Step 155 comprises determining the skylight light level based on the current time of day, as determined in step 151, and/or based on an ambient light level. Optionally, the skylight light level is further based on a manually configured or automatically determined geographical location. The one or more skylight light sources will be controlled according to this skylight light level between sunrise and sunset in step 113.

Step 157 comprises determining a skylight light level in a different manner than in step 155. Step 157 may comprise assigning a fixed light level to the skylight light level, for example. Step 157 may comprise keeping the sky blue just before sunrise and just after sunset and only letting the sky get dark(er) about 30 mins after sunset and bright(er) 30 min before sunrise. The one or more skylight light sources will be controlled according to this skylight light level between sunset and sunrise in step 113.

A fourth embodiment of the method of controlling one or more skylight light sources and one or more functional light sources is shown in Fig. 11. The fourth embodiment of Fig. 11 is an extension of the first embodiment of Fig. 6. In the embodiment of Fig. 11, step 103 is implemented by step 131 and step 105 is implemented by a step 181.

Furthermore, step 105 is a sub step of a step 171 which further comprises a sub step 183 and steps 111 and 113 are sub steps of a step 173 which further comprises a sub step 185.

Step 131 comprises determining the functional light level such that the functional light level stays above a minimum functional light level. Step 181 comprises determining the skylight light level. Step 183 comprises determining a peripheral light level. In step 171, the skylight light level and the peripheral light level are determined such that a combination of the skylight light level and the peripheral light level stays below a maximum non-functional light level. The minimum functional light level exceeds the maximum nonfunctional light level.

Step 173 comprises controlling the one or more functional light sources, the one or more skylight light sources, and the one or more peripheral light sources. Step 185 comprises controlling the one or more peripheral light sources according to the peripheral light level determined in step 183 while the one or more functional light sources are being controlled according to the functional light level determined in step 131.

The embodiments of Figs. 6-7 and 10-11 differ from each other in multiple aspects, i.e. multiple steps have been added, omitted and/or replaced. In variations on these embodiments, only a subset of these steps is added, omitted and/or replaced. Multiple embodiments may be combined. For example, the embodiment Fig. 11 may be combined with the embodiment of Fig. 6, 7, or 10.

Fig. 12 depicts a block diagram illustrating an exemplary data processing system that may perform the method as described with reference to Figs. 6-7 and 10-11.

As shown in Fig. 12, the data processing system 500 may include at least one processor 502 coupled to memory elements 504 through a system bus 506. As such, the data processing system may store program code within memory elements 504. Further, the processor 502 may execute the program code accessed from the memory elements 504 via a system bus 506. In one aspect, the data processing system may be implemented as a computer that is suitable for storing and/or executing program code. It should be appreciated, however, that the data processing system 500 may be implemented in the form of any system including a processor and a memory that is capable of performing the functions described within this specification.

The memory elements 504 may include one or more physical memory devices such as, for example, local memory 508 and one or more bulk storage devices 510. The local memory may refer to random access memory or other non-persistent memory device(s) generally used during actual execution of the program code. A bulk storage device may be implemented as a hard drive or other persistent data storage device. The processing system 500 may also include one or more cache memories (not shown) that provide temporary storage of at least some program code in order to reduce the quantity of times program code must be retrieved from the bulk storage device 510 during execution. The processing system 500 may also be able to use memory elements of another processing system, e.g. if the processing system 500 is part of a cloud-computing platform.

Input/output (I/O) devices depicted as an input device 512 and an output device 514 optionally can be coupled to the data processing system. Examples of input devices may include, but are not limited to, a keyboard, a pointing device such as a mouse, a microphone (e.g. for voice and/or speech recognition), or the like. Examples of output devices may include, but are not limited to, a monitor or a display, speakers, or the like. Input and/or output devices may be coupled to the data processing system either directly or through intervening VO controllers.

In an embodiment, the input and the output devices may be implemented as a combined input/output device (illustrated in Fig. 12 with a dashed line surrounding the input device 512 and the output device 514). An example of such a combined device is a touch sensitive display, also sometimes referred to as a “touch screen display” or simply “touch screen”. In such an embodiment, input to the device may be provided by a movement of a physical object, such as e.g. a stylus or a finger of a user, on or near the touch screen display.

A network adapter 516 may also be coupled to the data processing system to enable it to become coupled to other systems, computer systems, remote network devices, and/or remote storage devices through intervening private or public networks. The network adapter may comprise a data receiver for receiving data that is transmitted by said systems, devices and/or networks to the data processing system 500, and a data transmitter for transmitting data from the data processing system 500 to said systems, devices and/or networks. Modems, cable modems, and Ethernet cards are examples of different types of network adapter that may be used with the data processing system 500. As pictured in Fig. 12, the memory elements 504 may store an application 518. In various embodiments, the application 518 may be stored in the local memory 508, the one or more bulk storage devices 510, or separate from the local memory and the bulk storage devices. It should be appreciated that the data processing system 500 may further execute an operating system (not shown in Fig. 12) that can facilitate execution of the application 518. The application 518, being implemented in the form of executable program code, can be executed by the data processing system 500, e.g., by the processor 502. Responsive to executing the application, the data processing system 500 may be configured to perform one or more operations or method steps described herein.

Fig. 12 shows the input device 512 and the output device 514 as being separate from the network adapter 516. However, additionally, or alternatively, input may be received via the network adapter 516 and output be transmitted via the network adapter 516. For example, the data processing system 500 may be a cloud server. In this case, the input may be received from, and the output may be transmitted to, a user device that acts as a terminal.

Various embodiments of the invention may be implemented as a program product for use with a computer system, where the program(s) of the program product define functions of the embodiments (including the methods described herein). In one embodiment, the program(s) can be contained on a variety of non-transitory computer-readable storage media, where, as used herein, the expression “non-transitory computer readable storage media” comprises all computer-readable media, with the sole exception being a transitory, propagating signal. In another embodiment, the program(s) can be contained on a variety of transitory computer-readable storage media. Illustrative computer-readable storage media include, but are not limited to: (i) non-writable storage media (e.g., read-only memory devices within a computer such as CD-ROM disks readable by a CD-ROM drive, ROM chips or any type of solid-state non-volatile semiconductor memory) on which information is permanently stored; and (ii) writable storage media (e.g., flash memory, floppy disks within a diskette drive or hard-disk drive or any type of solid-state random-access semiconductor memory) on which alterable information is stored. The computer program may be run on the processor 302 described herein.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of embodiments of the present invention has been presented for purposes of illustration, but is not intended to be exhaustive or limited to the implementations in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope of the present invention.

The embodiments were chosen and described in order to best explain the principles and some practical applications of the present invention, and to enable others of ordinary skill in the art to understand the present invention for various embodiments with various modifications as are suited to the particular use contemplated.

Claims

22 CLAIMS:

1. A system (1,32,62) for controlling one or more skylight light sources (43- 45,93-95) and one or more functional light sources (19, 46-49), said system (1,32) comprising: at least one input interface (3, 33); at least one control interface (4, 38); at least one processor (5,35,65) configured to:

- receive, via said at least one input interface (3, 33), a signal from a light sensor (51), said signal being indicative of an ambient light level,

- determine a functional light level based on said ambient light level, said functional light level being reduced when said ambient light level increases,

- determine a skylight light level, which mimics a daylight light level, based on said ambient light level, said skylight light level being increased when said ambient light level increases,

- control, via said at least one control interface (4,38), said one or more functional light sources (19,46-49) according to said functional light level, and

- control, via said at least one control interface (4,38), said one or more skylight light sources (43-45,93-95) according to said skylight light level to mimic daylight while said one or more functional light sources (19,46-49) are being controlled according to said functional light level.

2. A system (1,32,62) as claimed in claim 1, wherein said at least one processor

(5.35.65) is configured to determine said functional light level such that said functional light level stays above a minimum functional light level and determine said skylight light level such that said skylight light level stays below a maximum skylight light level, wherein said minimum functional light level exceeds said maximum skylight light level.

3. A system (1,62) as claimed in claim 1 or 2, wherein said at least one processor

(5.65) is configured to determine said skylight light level based on a current time of day.

4. A system (1,62) as claimed in claim 3, wherein said at least one processor (5,65 is configured to determine said skylight light level further based on a manually configured or automatically determined geographical location.

5. A system (1,) as claimed in claim 1, wherein said at least one processor (5) is configured to:

- determine a peripheral light level, and

- control, via said at least one control interface (4), one or more peripheral light sources (57) according to said peripheral light level while said one or more functional light sources (19,46-49) are being controlled according to said functional light level.

6. A system (1,32,62) as claimed in claim 5, wherein said at least one processor (5,35,65) is configured to determine said functional light level such that said functional light level stays above a minimum functional light level and determine said skylight light level and said peripheral light level such that a combination of said skylight light level and said peripheral light level stays below a maximum non-functional light level, wherein said minimum functional light level exceeds said maximum non-functional light level.

7. A system (1,32,62) as claimed in claim 1 or 2, wherein said one or more skylight light sources (43-45,93-95) comprises a first light source (93-95) representing a sun portion and a second light source (43-45) representing a sky portion and said at least one processor (5,35,65) is configured to control said first light source (93-95) according to said skylight light level to mimic daylight.

8. A system (1,32,62) as claimed in claim 7, wherein said at least one processor (5,35,65) is configured to further control said second light source (43-45) according to said skylight light level.

9. A system (1,32,62) as claimed in claim 1 or 2, wherein said at least one processor (5,35,65) is configured to control said one or more skylight light sources (43- 45,93-95) according to said skylight light level between sunrise and sunset.

10. A system (1,32,62) as claimed in claim 9, wherein said at least one processor (5,35,65) is configured to control said one or more skylight light sources (43-45,93-95) according to a fixed light level between sunset and sunrise.

11. A method of controlling one or more skylight light sources and one or more functional light sources, said method comprising:

- receiving (101) a signal from a light sensor, said signal being indicative of an ambient light level;

- determining (103) a functional light level based on said ambient light level, said functional light level being reduced when said ambient light level increases;

- determining a skylight light level, which mimics a daylight light level, based on said ambient light level, said skylight light level being increased when said ambient light level increases;

- controlling (111) said one or more functional light sources according to said functional light level; and

- controlling (113) said one or more skylight light sources according to said skylight light level to mimic daylight while said one or more functional light sources are being controlled according to said functional light level.

12. A computer program product for a computing device, the computer program product comprising computer program code to perform the method of claim 11 when the computer program product is run on a processing unit of the computing device.