FIELD OF THE INVENTION

The present invention relates to a luminaire controller, a luminaire including the luminaire controller, a lighting system, and a method for controlling a luminaire. In particular, the invention relates to a luminaire controller for a luminaire which comprises a first source of visible rays and a second source of invisible rays.

BACKGROUND OF THE INVENTION

US 2016/0153619 A1 shows a luminaire for emitting an electromagnetic radiation, comprising a first LED radiation source for generating a first portion of the radiation in the form of a white light. Furthermore, the luminaire comprises a second LED radiation source for generating a second portion of the radiation, wherein the second portion only has radiation having wavelengths within the wavelength range of approximately 280 nm to approximately 425 nm. Preferably, the luminaire furthermore comprises a control unit for driving the first LED radiation source and the second LED radiation source, wherein the control unit is fashioned in such a way that the intensity of the first portion is greater than zero if the intensity of the second portion is greater than zero.

SUMMARY OF THE INVENTION

It can be seen as an object of the present invention to provide a luminaire controller, a luminaire including the luminaire controller, a lighting system, and a method for controlling a luminaire which allow operating a luminaire with an increased radiant flux of a source of invisible rays while ensuring eye safety of human users.

In a first aspect of the present invention a luminaire controller for a luminaire which comprises a first source of visible rays and a second source of invisible rays is presented. The luminaire controller is configured for limiting a radiant flux value of the second source based on a radiant flux value of the first source and a sensor value determined by a sensor.

Since the luminaire controller is configured for limiting a radiant flux value of the second source based on a radiant flux value of the first source and a sensor value determined by a sensor, eye safety of users can be improved. The invisible rays can be harmful for the eyes of the user. When visible rays with a certain radiant flux value hit the user’s eyes, the user has a reflex for closing his eyes or looking into another direction. Limiting the radiant flux of the second source based on the radiant flux value of the first source and the sensor value allows to ensure that the radiant flux value of the second source is limited to a value which does not harm the user’s eyes.

Increasing the radiant flux value of the first source allows increasing the radiant flux value of the second source. For example, the radiant flux value of the first source can be adjusted by adjusting a correlated color temperature (CCT) of the visible rays provided by the first source.

Since the luminaire controller does not only consider the radiant flux value of the first source, but also the sensor value, additional factors can be considered for limiting the radiant flux value of the second source. For example, an occupancy of a human user of a space in which the luminaire is arranged or radiant flux values of other light sources, e.g., natural light sources or other artificial light sources can be considered for limiting the radiant flux value of the second source. This can allow for increasing the radiant flux value of the second source. For example, if no human user is in the space in which the luminaire is arranged, the second source can be operated with a higher radiant flux value as eye safety is not an issue. Furthermore, typical glare effects influencing human user’s field of view (FoV) and eye movements can be taken into account. Disturbing objects, such as reflecting or translucent objects and in particular reflections at or transmissions through these objects can be taken into account for limiting the radiant flux value of the second source. Reflecting or translucent objects can for example include glass objects such as windows that can cross a beam path of the rays.

The luminaire controller can for example be used for improving performance while ensuring eye safety during infrared (IR) and/or ultraviolet (UV) data transmission, such as light fidelity (Li-Fi). The luminaire controller can also allow to improve performance while ensuring eye safety during IR charging, or ultraviolet A (UVA) disinfection. For example, charging and disinfection can be performed faster, as the second source can provide higher radiant flux values while eye safety is ensured.

The visible rays and the invisible rays directed into a same direction can have radiant density values proportional to the radiant flux values of the first source and the second source, e.g., the visible rays and the invisible rays can have the same directional characteristics. This can allow to ensure eye safety in the respective direction in which the radiant density values of the visible and invisible rays are proportional to the radiant flux values of the first and second source. A human user typically will not look into the direction of the first source for a prolonged time as visible rays provided by the first source generate a glare effect which is not appreciated due to the physical characteristics of human users. The eyes own sensitivity can be reduced by closing the iris due to the visible rays impinging on the eyes. The eyelid serves as additional protection against the invisible rays, allowing to reduce mid- and long-term exposure effects of invisible rays within the eyes.

Limiting the radiant flux value of the second source can for example be performed by setting a maximal radiant flux value. The radiant flux value of the second source can then be adjusted between zero and the maximal radiant flux value. Alternatively, limiting the radiant flux value of the second source can be performed by adjusting the radiant flux value of the second source to a predetermined radiant flux value based on the radiant flux value of the first source and the sensor value. For example, a predetermined function for determining the maximal radiant flux value or a look up table (LUT) with maximal radiant flux values of the second source can be provided in dependence of the radiant flux value of the first source and the sensor value. The radiant flux value of the first source and the sensor value can be combined into a single value and used as input into the predetermined function or for looking up a respective maximal radiant flux value in the LUT.

The luminaire controller can include a processor. The processor can be configured for processing data and/or signals. The luminaire controller can also include a computer readable medium for storing data, for example computer program code.

The luminaire controller can be included in a luminaire. The luminaire controller can for example be included in a luminaire arranged at a ceiling for performing IR charging or beamed Li-Fi. This can allow usage of high intensity IR beams for charging while ensuring eye safety. The luminaire can furthermore include the first source and the second source. The luminaire can also include the sensor. Alternatively or additionally, one or more sensors can be separate units. The luminaire can be included in a lighting system.

The lighting system can furthermore include a lighting control system. The lighting system can also include the one or more sensors.

The lighting control system can be configured for determining the radiant flux value of the second source based on the radiant flux value of the first source and the sensor value. The lighting system can provide control signals to the luminaire controller for causing the luminaire controller to limit the radiant flux of the second source based on the radiant flux value of the first source and the sensor value. Alternatively or additionally, the luminaire controller can be configured for determining the radiant flux value of the second source based on the radiant flux value of the first source and the sensor value.

The sensor can be configured for measuring the sensor value or more than one sensor value. Alternatively, one or more sensors can be configured for measuring one or more sensor values. If more than one sensor value is measured, the as measured sensor values can for example be processed in order to determine a processed sensor value which can be used as the sensor value. Alternatively, the lighting control system and/or the luminaire controller can be configured for limiting the radiant flux value of the second source based on the radiant flux value of the first source and the sensor values measured by the sensor or sensors.

The sensor value can include the radiant flux value of the first source, e.g., if the sensor is arranged such that the sensor can measure the radiant flux value of the first source. In this case, limiting the radiant flux value of the second source based on the sensor value is automatically also based on the radiant flux value of the first source. The radiant flux value of the first source does not have to be considered twice in this case.

The sensor value can be determined based on at least one of: a radiant flux value of visible rays in a space in which the luminaire is arranged, a presence value of a user, a position value of a user, a FoV value of a user, a characteristic of a user, an eye protection value of a user, a position value of a target object, a position value of a disturbing object, a predicted movement path of a user, a predicted movement path of a target object a predicted movement path of a disturbing object.

The sensor can measure the radiant flux value of visible rays in the space in which the luminaire is arranged, the presence value of the user, the position value of the user, the FoV value of the user, the characteristic of the user, the eye protection value of the user, the position value of the target object, and the position value of the disturbing object. The luminaire controller can be configured for determining a sensor value based on the measured values. The sensor value can also be determined by the lighting control system based on the measured values.

The radiant flux value of the visible rays in the space in which the luminaire is arranged can include the radiant flux value of the first source. The radiant flux value of the visible rays in the space in which the luminaire is arranged corresponds to a radiant flux value of visible rays provided by all light sources that provide rays for that space, for example including the visible rays provided by the first source, daylight provided by the sun, visible rays provided by other artificial light sources, and reflections of light provided by the sun, e.g., moonlight or visible rays reflected by a mirror or other reflecting object.

Characteristics of a user can for example include an age of a user, a pupil size of a user at a specific lighting condition, a race of a user, and a duration a user has been exposed to rays of the luminaire. A pupil size of a user depends on lighting conditions. The pupil size is larger for lower light conditions, e.g., lower brightness or lower radiant flux values. The pupil size is age dependent, i.e., older users typically have a smaller pupil size than younger users. Furthermore, a rate of pupil change with age decreases at higher luminance level. Pupil size is also race dependent. For example, Asians have larger pupils and a thicker iris than Caucasians. Therefore, damage to eyes can also be race dependent. Typically, the eyes of an Asian user let more damaging invisible rays into the eyes. Asian users are also at a higher risk for glaucoma. Depending on the duration a user has been exposed to rays of the luminaire, the pupils of eyes of the user will be more or less open. Less open pupils can allow a reduced damage by invisible rays.

The eye protection value of a user can include a type of eyeprotection worn by a user, such as eyeglasses. If eye protection is worn by a user, the radiant flux value of the second source may be higher while ensuring eye safety.

The target object can for example be a user device or a surface. The user device can for example be charged using IR rays or a communication link can be established using Li-Fi. The surface can for example be disinfected using UV rays.

The disturbing object can for example be a reflecting object that reflects rays or a translucent object which allows rays to pass through it.

The lighting control system and/or the luminaire controller can be configured for adjusting the radiant flux value of the second source to a current eye safety limit estimated based on the radiant flux value of the visible rays in the space in which the luminaire is arranged. This allows to take into account other light sources when limiting the radiant flux value of the second source. The presence value of a user determines whether a user is present is the space in which the luminaire controlled by the luminaire controller is arranged. The luminaire controller can in this case for example be configured for increasing the radiant flux value of the second source based on the presence value, e.g., such that the radiant flux value of the second source is not limited in order to ensure eye safety. This allows increasing the radiant flux value of the second source in case that no human user is present in the space in which the luminaire is arranged as eye safety is not an issue. The presence value of a user can be determined by a presence sensor. The presence sensor can be included in the lighting system, for example as a separate unit or as part of the luminaire.

The position value of a user determines a position of a user relative to the luminaire in the space in which the luminaire controlled by the luminaire controller is arranged. The luminaire controller can in this case for example be configured for increasing the radiant flux value of the second source based on the position value, e.g., the radiant flux value of the second source may be limited less severely with increasing distance from the luminaire. This allows increasing the radiant flux value of the second source in case that a human user has a large distance from the second source. The position value of a user can be determined by a position sensor. The position sensor can be included in the lighting system, for example as a separate unit or as part of the luminaire.

The FoV value of a user determines the volume from which the eyes of the user receive rays. The luminaire controller can in this case for example be configured for increasing the radiant flux value of the second source based on the FoV value, e.g., the radiant flux value of the second source may be limited less severely or not at all if the luminaire is not in the FoV of the user. This allows increasing the radiant flux value of the second source in case that eyes of the human user do not directly receive rays from the luminaire. Furthermore, reflections can be taken into account in order to allow a further increase of the radiant flux value of the second source.

The FoV value of a user can for example be determined using a sensor in form of an image sensor based safety system, such as a camera based safety system. The image sensor based safety system can be included in the lighting system, for example as a separate unit or as part of the luminaire.

The image sensor based safety system can be configured for determining a presence value of a user, a position value of a user, a FoV value of a user, a position value of a target object, a position value of a disturbing object, a predicted movement path of a user, a predicted movement path of a target object, and/or a predicted movement path of a disturbing object. This can allow to optimize the radiant flux value of the second source while ensuring eye safety of the user.

The image sensor based safety system can include an image sensor, e.g., a camera, for receiving video information and a processor for processing the video information. The image sensor based safety system can also be configured for recognizing users and/or objects. The image sensor based safety system can also be configured for recognizing whether an object is translucent and/or reflecting. The image sensor based safety system can further be configured for detecting glare effects at a user. For example, if the eyes of a user are hit by rays, the image sensor based safety system can detect a blinking of eyelids and/or that pupils of the eyes become smaller. This can be taken into account when limiting the radiant flux value of the second source in order to improve eye safety. This can allow to reduce long-term exposure issues of invisible rays.

The image sensor based safety system can for example use image processing methods, e.g. machine learning methods, for recognizing users, target objects, disturbing objects and/or for determining their position, FoV, orientation, predicted movement path, etc. The image sensor based safety system can for example detect when disturbing objects, such as transparent or reflecting objects cross the path of the invisible rays. This can lead to reflections which may lead to eye damage in long term exposure. This can be taken into account when limiting the radiant flux value of the second source in order to reduce eye damage.

Alternatively or additionally, a change of a position of an object, such as a window, can be detected by radio frequency (RF) sensing RF sensing, e.g., by analysing disturbances in wireless signals between luminaires or the luminaire and the lighting control system. This allows determining change of position of an object without the need of an image sensor based safety system.

The image sensor based safety system can furthermore be configured for detecting as a sensor value when a user looks into the invisible rays provided by the second source. The sensor value may for example be negative, e.g., 0 if the user does not look into the invisible rays and positive, e.g., 1, if the user looks into the invisible rays. This allows to adjust the radiant flux value of the second source when a user looks into the invisible rays provided by the second source.

The luminaire controller can be configured for communicating status information to the lighting control system. Status information can for example include a current radiant flux value of the second source and/or the first source. This can allow to improve limiting the radiant flux value of the second source. Furthermore, this can allow to extend a timespan for generating invisible rays, for example to keep a charging or disinfection effect of the invisible rays constant. The lighting control system can be configured for adjusting or providing an adjustment range for the radiant flux value of the first source when the radiant flux value of the second source is above a certain threshold value. The lighting control system can also for example be configured for adjusting a CCT of the first source when the radiant flux value of the second source is above a certain threshold value. This can allow to improve eye safety.

The luminaire controller can be further configured for adjusting a direction of invisible rays provided by the second source based on the sensor value.

The luminaire controller can furthermore be configured for adjusting the direction of visible rays provided by the first source. The luminaire controller can be configured for performing beamsteering for adjusting the direction of the invisible and/or visible rays. The beamsteering can also be performed by the lighting control system. The lighting control system can be further configured for providing corresponding signals for adjusting the direction of the invisible rays and/or visible rays to the luminaire controller.

The luminaire controller can furthermore be configured for beamforming the rays into one or more beams. The luminaire controller can be configured for adjusting an output power for each of the beams based on the sensor value. Alternatively or additionally, the lighting control system can be configured for beamforming the rays into one or more beams. The lighting control system can be configured for adjusting an output power for each of the beams based on the sensor value.

The luminaire controller can be further configured for modulating the visible rays provided by the first source and/or the invisible rays provided by the second source, such that the source of origin of the respective rays can be identified.

Modulation can be performed by modulating one or more properties of a periodic waveform of the rays provided by the sources, e.g., by frequency modulation (FM) or by amplitude modulation (AM). Alternatively or additionally, the lighting control system can be configured for providing control signals to the luminaire controller for modulating the visible rays provided by the first source and/or invisible rays provided by the second source. This allows identifying the source of origin of the respective rays. This can be taken into account when limiting the radiant flux value of the second source such that higher radiant flux values can be used while ensuring eye safety. The luminaire controller can be further configured for adjusting the radiant flux value of visible rays in a space in which the luminaire is arranged based on the sensor value.

The radiant flux value of the visible rays in the space in which the luminaire is arranged can for example be adjusted by adjusting the radiant flux value of the first source, adjusting a position of window blinds, or adjusting a radiant flux value of daylight provided by a skylight daylight system. This allows to ensure a consistent lighting in the space in which the luminaire is arranged and can allow to keep a lighting scene.

In a further aspect of the present invention a luminaire is presented which includes a luminaire controller according to at least one of the claims 1 to 5 or any embodiment of the luminaire controller. The luminaire furthermore includes a first source of visible rays and a second source of invisible rays.

The first source is configured for providing rays in a wavelength range which is visible for a human user, e.g., rays in a wavelength range between 380 nm and 760 nm.

The second source is configured for providing rays in a wavelength range which is invisible for a human user. Some wavelengths may be visible for some human users while for the average human users the rays are invisible.

The luminaire can further include the sensor for determining the sensor value.

The second source can be configured for providing IR and/or UV rays, i.e., IR rays, UV rays, or both IR and UV rays.

IR rays can for example include near infrared (IR-A) rays, middle infrared (IR-B) rays, and far infrared (IR-C) rays. IR rays can for example have a wavelength between 760 nm and 1.00 mm, e.g., between 760 nm and 1400 nm, between 1400 nm and 3000 nm, or between 3000 nm and 1.00 mm.

UV rays can for example include vacuum ultraviolet (VUV), extreme ultraviolet (EUV), hydrogen Lyman-alpha (H Lyman-), far ultraviolet (FUV), ultraviolet C (UVC), middle ultraviolet (MUV), ultraviolet B (UVB), near ultraviolet (NUV), and UVA. UV rays can for example have a wavelength between 100 nm and 400 nm, between 10 nm and 200 nm, between 10 nm and 121 nm, between 121 nm and 122 nm, between 122 nm and 200 nm, between 100 nm and 280 nm, between 200 nm and 300 nm, between 280 nm and 315 nm, between 300 nm and 400 nm, or between 315 nm and 400 nm.

The second source can include at least two lasers for providing rays with at least two different wavelengths or wavelength ranges. The rays with different wavelengths or wavelength ranges can be used for different tasks. For example, the rays with a first wavelength can be used for charging and the rays with a second wavelength can be used for data transmission. Alternatively, rays of one of the wavelengths can also be used for disinfection. The usage for the different tasks can be based on the sensor value. For example, the wavelength for charging and data transmission may be interchanged in dependence of whether a human user is present or not. It may also be interchanged based on any other sensor value. One wavelength can also be used for performing several tasks, e.g., charging and data transmission. The invisible rays can be used for charging, data communication, and/or UV disinfection.

The second source can for example include a UV unit, e.g., an UV light emitting diode (LED), an UV LED array, or an UV laser, for providing UV rays and an IR unit, e.g., an IR laser, an IR LED, or an IR LED array, for providing IR rays. The luminaire can be configured for using UV rays for data communication when a moisture value is above a threshold moisture value and for using IR rays for data communication when a moisture value is below or equal to the threshold moisture value. The moisture value can be determined by a moisture sensor arranged in the space in which the luminaire is arranged. The lighting control system and/or the luminaire controller which controls the luminaire can be provided with the moisture value in order to determine which rays are to be used for the data communication. For example, when water sprinklers are activated or heavy rain is present in the space in which the luminaire is arranged, e.g., in an outdoor application, IR rays may be absorbed by moisture in the air. Using UV rays in case of high moisture can allow to ensure an improved operation of the data communication.

The luminaire can be configured for performing beamsteering of the visible rays and the invisible rays.

The beamsteering can for example be performed by the luminaire controller and/or the lighting control system. The beamsteering can be used for adjusting the direction of the visible rays and the invisible rays. The directions of the rays can be taken into account when limiting the radiant flux values of the second source and/or the first source. This can allow increased radiant flux values of the second source while ensuring eye safety.

The luminaire can be configured for performing beamsteering based on the sensor value, e.g., the radiant flux value of the visible rays in the space in which the luminaire is arranged and/or a directionality of the visible rays in the space in which the luminaire is arranged. This can allow for an improved performance of the luminaire while ensuring eye safety. The performance of the luminaire includes an improved efficiency of performing tasks of the luminaire, such as disinfection, charging, and/or data transmission using the invisible rays.

The luminaire can be configured for providing beamsteered UV rays for disinfection. For example a first object to be disinfected which is in a line of sight (LOS) of the luminaire can be disinfected easily. A second object to be disinfected which is not in the LOS can for example only be reached via reflecting the UV rays at a reflecting object. The luminaire can be configured for taking this into account and adjust the radiant flux value of the second source accordingly, e.g., increasing the radiant flux value of the second source for disinfecting the second object. This can allow an improved disinfection.

The luminaire can be configured for providing rays with a specific wave length or wave length range optimized for performing a specific task of the luminaire. Alternatively or additionally, the luminaire controller can be configured for causing the first source and/or the second source of the luminaire to provide rays with a specific wave length or wave length range optimized for performing a specific task of the luminaire. Specific tasks of the luminaire can include charging, data communication, disinfection, and growing plants. The luminaire can for example be configured for providing a specific wave length or wave length range optimized for charging, for data communication, for disinfection, or for growing plants. The specific wave length or wave length range can be provided by the first source or the second source. This can allow an improved performance of a specific task of the luminaire while ensuring eye safety.

The luminaire can for example be configured for providing rays with certain wavelengths to plants. For example, beamsteered rays of predetermined wavelengths can be provided to individual plants depending on the plant type in order to optimize growth. This allows to augment growth of the plants as besides daylight and light from other luminaires, rays of predetermined wavelengths can be provided to the plants while ensuring eye safety of users. For example, the provision of rays with certain wavelengths to plants can be performed based on the sensor value, such as the presence value of a user. The luminaire can for example provide the plants with the rays with certain wavelengths in case that no user is present in the space in which the luminaire is arranged. This allows to improve eye safety.

The luminaire can be further configured for performing the beamsteering of the visible rays and the invisible rays such that an outline of a volume of the invisible rays is made visible by the visible rays. For example, the visible rays can have such a high contrast that dust particles in the air reflect the visible rays to the eyes of the user and allow the user to detect the volume in which the invisible rays are present. This allows to improve eye safety as users can receive direct feedback about the volume in which invisible rays are present. The lighting control system and/or the luminaire controller can be configured for performing the beamsteering of the visible rays and the invisible rays such that the outline of the volume of the invisible rays is made visible by the visible rays. The lighting control system can provide control signals to the luminaire controller for causing it for perform the beamsteering for the luminaire.

The luminaire can be configured for directing visible rays into the eyes of the user in order to cause the eyelid of the user to close. This can serve for conditioning the eyes of the user in order to improve eye safety. For example, when a user is approaching a volume of the invisible rays, this can allow to improve eye safety.

The luminaire can be configured for limiting the radiant flux value of the second source based on which user is present in the space in which the luminaire is arranged. For example, the luminaire can at first limit the radiant flux value of the second source to a lower value and increase it to a higher value when the user that is exposed to the invisible rays provided by the second source is identified. The luminaire can for example be connected to the image sensor based safety system for tracking users and their individual exposure to invisible rays and visible rays and adjust the radiant flux values accordingly. The luminaire can be configured for adjusting the radiant flux values of the first and second source based on the identified user. This allows to improve performance of the luminaire.

The luminaire can also be configured for adjusting the radiant flux value of the second source when the user is approaching the volume of the invisible rays based on a light setting experienced by the user before entering the volume of the invisible rays. This can allow to improve eye safety.

The luminaire can be configured for increasing radiant flux value of the first source based on a required radiant flux value of the second source, e.g., in case that a higher radiant flux value of the second source is required for performing the task of the second source. For example, in case that charging or UV disinfection requires a higher radiant flux value of the second source, the radiant flux value of the first source can be increased to ensure eye safety. This can allow to ensure that the tasks of the luminaire can be performed while ensuring eye safety. Alternatively or additionally, the luminaire can be configured for increasing the radiant flux value of visible rays in the space in which the luminaire is arranged based on a required radiant flux value of the second source.

The luminaire can be configured for adjusting a wavelength of the invisible rays provided by the second source and/or an aperture of the second source based on at least one of: a radiant flux value of the visible rays in the space in which the luminaire is arranged, a directionality of the visible rays in the space in which the luminaire is arranged compared to the invisible rays, a duration for which a user is present in the space in which the luminaire is arranged. The invisible rays can for example be used for charging. In this case, charging benefits from an as small as possible dot on a receiver photodiode of a user device to be charged in order to maximize transmission efficiency. A smaller dot has the caveat that this may cause larger damage to a retina when it hits an eye of a user. Adjusting the wavelength of the invisible rays and/or the aperture of the second source can allow to increase eye safety.

The luminaire can be configured for an indoor use or an outdoor use. For example, luminaires for outdoor use can be weatherproof, e.g., waterproof. For indoor use, the luminaire can for example be used in an office space, a factory, or a hospital.

In a further aspect of the present invention a lighting system is presented. The lighting system includes a plurality of luminaires according to at least one of the claims 6 to 10 or any embodiment of the luminaire. Furthermore, the lighting system includes one or more sensors, and a lighting control system for controlling the luminaires.

The one or more sensors can be configured for determining the sensor value or the sensor values.

The lighting control system can include a processor. Furthermore, the lighting control system can include a computer readable medium.

The lighting control system can be configured for determining a limiting radiant flux value of a second source of a respective luminaire based on the radiant flux value of a first source of the respective luminaire and the sensor value determined by the sensor or sensors. The lighting control system can be configured for providing a control signal to the luminaire controller of the respective luminaire for causing the luminaire controller to limit the radiant flux value of the second source of the respective luminaire based on the radiant flux value of the first source of the respective luminaire and the sensor value or sensor values.

The lighting control system can be configured for reducing the radiant flux value of the visible rays in the space in which a respective luminaire is arranged when the respective luminaire scans for a target to perform its function. For example, the luminaire can scan for a target object, such as a user device to be charged or a surface to be disinfected. Reducing the radiant flux value of the visible rays in the space in which the respective luminaire is arranged can allow a faster detection of a target object for which a function is to be performed. For example, an IR photodiode to be provided with IR rays can be detected faster as the responsiveness of the IR photodiode can be increased. Additionally, the lighting control system can be configured for increasing the radiant flux value of the visible rays in the space in which the respective luminaire is arranged when the respective luminaire performs its function, e.g., charging the user device or disinfecting the surface. This can allow a faster charging an/or faster disinfection while ensuring eye safety. Furthermore, the lighting control system can adjust the radiant flux value of the second source of the respective luminaire based on the radiant flux value of the first source of the respective luminaire and the sensor value. This allows an even more improved eye safety and increased performance for the function of the second source. For example, when a human user is present in the space in which the luminaire is arranged the radiant flux value of the second source may be limited to a first threshold radiant flux value while it may be limited to a second threshold radiant flux value while no human user is present. The first threshold radiant flux value is preferably lower than the second threshold radiant flux value.

The lighting system can be configured for performing beamsteering of one or more of the luminaires. The lighting system can be configured for adjusting a current lighting scene based on a current location of a target object, e.g. a to be charged user device, such that a two dimensional light distribution has higher values closer to the current location of the target object than further away of the target object. This can allow an improved eye safety as eye opening in the current location of the target will be smaller and thus retina damage can be reduced.

The one or more sensors can include an image sensor based safety system. The image sensor based safety system can be configured for determining a presence value of a user, a position value of a user, a FoV value of a user, a position value of a target object, a position value of a disturbing object, a predicted movement path of a user, a predicted movement path of a target object, and/or a predicted movement path of a disturbing object. The image sensor based safety system can include an image sensor, e.g., a camera, for receiving video information and a processor for processing the video information.

The lighting system can for example be a wireless charging system. The wireless charging system can be configured for charging user devices such as smart phones using the invisible rays provided by the second source, e.g., IR rays. The wireless charging system can be configured for performing image sensor based hazard pre-detection using the image sensor based safety system. Therefore, the invisible rays and/or visible rays may furthermore be modulated. The image sensor based safety system can be configured for tracking users in order to determine an eye sensitivity of the users. The wireless charging system can be configured for adjusting the radiant flux values of the first and second sources for reducing eye hazards.

In a further aspect of the present invention a method for controlling a luminaire which comprises a first source of visible rays and a second source of invisible rays is presented. The method comprises the step: limiting a radiant flux value of the second source based on a radiant flux value of the first source and a sensor value determined by a sensor.

The method can comprise a step: determining the sensor value based on at least one of: a radiant flux value of visible rays in a space in which the luminaire is arranged, a presence value of a user, a position value of a user, a FoV value of a user, a characteristic of a user, an eye protection value of a user, a position value of a target object, a position value of a disturbing object, a predicted movement path of a user, a predicted movement path of a target object a predicted movement path of a disturbing object.

In a further aspect of the present invention a computer program product for controlling a luminaire is presented. The computer program product comprises program code means for causing a processor to carry out the method as defined in claim 13, or any embodiment of the method, when the computer program product is run on the processor.

In a further aspect a computer readable medium having stored the computer program product of claim 14 is presented. Alternatively or additionally the computer readable medium can have the computer program product according to any embodiment of the computer program product stored.

It shall be understood that the luminaire controller of claim 1, the luminaire of claim 6, the lighting system of claim 11, the method of claim 13, the computer program product of claim 14, and the computer readable medium of claim 15 have similar and/or identical preferred embodiments, in particular, as defined in the dependent claims. It shall be understood that a preferred embodiment of the present invention can also be any combination of the dependent claims or above embodiments with the respective independent claim.

These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following drawings:

Fig. 1 shows schematically and exemplarily an embodiment of a luminaire including an embodiment of a luminaire controller;

Fig. 2 shows schematically and exemplarily an embodiment of a lighting system;

Fig. 3 shows an exemplary control curve for limiting a radiant flux value of the second source in dependence of a radiant flux value of the first source; and

Fig. 4 shows schematically and exemplarily an embodiment of a method for controlling a luminaire.

DETAILED DESCRIPTION OF EMBODIMENTS

Fig. 1 shows schematically and exemplarily an embodiment of a luminaire 100 including an embodiment of a luminaire controller 10.

The luminaire 100 further comprises a first source 20 of visible rays and a second source 30 of invisible rays.

The first source 20 provides visible light of wavelengths between 380 nm and 760 nm. In other embodiments, the first source 20 may also provide a different range of wavelengths in the visible spectrum.

The second source 30 includes an IR laser array 32 for providing IR rays and an UV LED array 34 for providing UV rays. In other embodiments, the laser array may also be replaced by an LED array or one or more LEDs. The UV LED array can also be replaced by a UV laser array or one or more LEDs. Instead of LEDs, LED arrays, or laser arrays, any other source for providing rays may be used. In this embodiment, the second source 30 can provide either IR rays or UV rays. In other embodiments, the second source can be configured for providing infrared and/or ultraviolet rays. The second source may also be configured for providing invisible rays of a limited wavelength range, e.g., only one of IR or UV rays. The IR laser array 32 provides IR rays with a wavelength between 760 nm and 1.00 mm. In other embodiments, the IR laser array may also provide IR-A, IR-B, or IR-C rays.

The UV LED array 34 provides UVA rays with a wavelength between 315 nm and 400 nm. In other embodiments, the UV LED array may also provide UV rays with other wavelengths, e.g., between 100 nm and 400 nm.

The luminaire 100 furthermore includes a transceiver 40 for communicating data with a lighting control system, sensors, and/or other luminaires (not shown).

In this embodiment, the luminaire 100 additionally includes a presence sensor 50. The presence sensor 50 is optional. In other embodiments, other sensors may be included in the luminaire.

Presence sensor 50 measures whether a user is present in the room in which the luminaire 100 is arranged. If a user is present in the room the presence sensor determines the presence value of a user to be 1. If no user is present in the room the presence sensor determines the presence value of a user to be 0.

The luminaire controller 10 controls the functions of the luminaire 100. The luminaire controller 10 includes a processor 12 and a computer readable medium in form of a memory 14. In this embodiment, memory 14 stores a computer program product for controlling the luminaire 100. The computer program product comprises program code means for causing the processor 12 to carry out a method for controlling the luminaire 100, e.g., the method presented with respect to Fig. 4, when the computer program product is run on the processor 12.

The processor 12 can process data, such as a radiant flux value of the first source 20 and a presence value of a user determined by the presence sensor 50. The radiant flux value of the first source 20 is provided to the processor 12 by the first source 20. The presence value of a user is provided to the processor 12 by the presence sensor 50. In particular, the luminaire controller 10 limits a radiant flux value of the second source 30 based on the radiant flux value of the first source 20 and the presence value determined by the presence sensor 50. Therefore, the processor 12 determines a limiting radiant flux value of the second source 30.

The luminaire controller 10 uses a predetermined function to determine the limiting radiant flux value of the second source 30. The predetermined function corresponds to a control curve if the presence value of a user is 1 and to a maximal radiant flux value of the second source 30 if the presence value of a user is 0. The control curve can for example be the exemplary control curve for limiting a radiant flux value of the second source in dependence of a radiant flux value of the first source as presented with respect to Fig. 3.

The limiting radiant flux value of the second source 30 is then used by the luminaire controller 10 to set the radiant flux value of the second source 30 to the limiting radiant flux value of the second source 30 in order to maximize performance of the task to be performed by the luminaire 100.

The luminaire 100 can be used for performing IR charging using the IR laser array 32, Li-Fi data communication using the IR laser array 32, or UV disinfection using the UV LED array 34.

In other embodiments, the radiant flux value of the second source may also be set between 0 and the limiting radiant flux value of the second source based on control signals received from a lighting control system.

In other embodiments, further sensors may be provided, e.g., an image sensor based safety system. The sensor value can be determined based on at least one of: a radiant flux value of visible rays in a space in which the luminaire is arranged, a presence value of a user, a position value of a user, a FoV value of a user, a characteristic of a user, an eye protection value of a user, a position value of a target object, a position value of a disturbing object, a predicted movement path of a user, a predicted movement path of a target object a predicted movement path of a disturbing object.

Fig. 2 shows schematically and exemplarily an embodiment of a lighting system in form of an IR charging system 200 arranged in a room 205.

The IR charging system 200 includes a plurality of luminaires 210, 211, and 212 arranged at the ceiling in the room 205. The ceiling luminaires 210, 211, and 212, in this embodiment, include a first source of visible rays and a second source of invisible rays (not shown). The luminaires can for example be luminaires with identical components as luminaire 100 presented in Fig. 1. The IR charging system 200 furthermore includes sensors in form of camera based safety system 215 and presence sensor 216, as well as a lighting control system 250. Instead of the camera based safety system, any other image sensor based safety system may be provided.

The IR charging system 200 can be used for wireless charging by means of IR rays. For example, target objects, e.g., user devices such as smartphones 221 and 222 can be charged using IR rays 231. In this case, the user devices can for example include an integrated photovoltaic (PV) cell for charging. The user devices can thus be charged by daylight and by the IR rays. IR rays can allow to improve charging efficiency. Using IR rays furthermore can allow to reduce size of the luminaire.

Each of the luminaires 210, 211, and 212 can be arranged such that it can provide a sufficient radiant flux value that allows charging a user device in an associated volume. For example, smartphone 221 can be charged by luminaire 211 and smartphone 222 carried by user 240 can be charged by luminaire 212.

In other embodiments, the ceiling luminaires can allow for IR charging, UV disinfection, and/or beamed Li-Fi.

The user 240 may look into the luminaire 212 such that invisible rays 241 may hit his eyes. Furthermore, reflected invisible rays may hit the user’s eyes. Therefore, the IR charging system 200 needs to ensure eye safety of the users. In the following it is discussed in more detail how eye safety can be ensured using the IR charging system while allowing to perform IR charging with high radiant flux values of the second source.

In this embodiment, the camera based safety system 215 determines a presence value of a user 240, a position value of a user 240, a FoV value of a user 240, a characteristic of a user, an eye protection value of a user, a position value of a user device, a position value of a disturbing object, a predicted movement path of a user, a predicted movement path of a user device, and a predicted movement path of a disturbing object. Disturbing objects can be reflecting objects or translucent objects. In this embodiment, reflecting objects include all reflecting surfaces, such as window 260.

In other embodiments, the position value and/or predicted movement path of any other target object instead of the user device may be determined by an image sensor based safety system or another sensor.

The camera based safety system 215 uses image processing techniques for processing the video information received from cameras included in the camera based safety system 215. The image processing techniques include machine learning algorithms for recognizing object type and properties. For example, a user device and its properties can be identified, e.g., whether the user device can be charged using IR rays and which wavelength and/or radiant flux value is required.

Additionally, presence sensor 216 allows to determine whether user 240 is present at his respective desk which is associated to the luminaire 211. This allows to save calculation effort, as the presence value does not need to be determined by the camera based safety system but can be determined using an easier sensor. In case that a user is present the radiant flux value of the second source of the luminaire 211 is limited. In the present situation, the radiant flux value of the second source of the luminaire 211 does not need to be limited as no user is present in the volume to which the luminaire 211 provides invisible rays with a high radiant intensity value.

The lighting control system 250 controls the luminaires 210, 211, and 212 and other components of the lighting system 200. The lighting control system 250 includes a processor 252 and a computer readable medium in form of a memory 254. In this embodiment, memory 254 stores a computer program product for controlling the luminaires 210, 211, and 212. The computer program product comprises program code means for causing the processor 252 to carry out a method for controlling the luminaires 210, 211, and 212, e.g., the method presented with respect to Fig. 4, when the computer program product is run on the processor 252.

When the camera based safety system 215 has identified a user device to be charged, the lighting control system 250 adjusts the direction of the invisible rays of one or more of the luminaires based on that information. The lighting control system 250 performs beamsteering of the visible rays and the invisible rays. In this embodiment, the lighting control system 250 besides directing the invisible rays to the user devices 221 and 222, additionally performs the beamsteering of the visible rays and the invisible rays such that an outline of a volume of the invisible rays is made visible by the visible rays (not shown). This is possible by providing a high contrast, such that dust particles in the air of the room 205 are illuminated by the visible rays.

In other embodiments, this processing can also be performed locally on a respective luminaire, for example a luminaire controller of a respective luminaire can be configured for adjusting a direction of invisible rays provided by the second source based on the sensor value. The respective luminaire can also be configured for performing beamsteering of the visible rays and the invisible rays. In particular, the respective luminaire can be configured for performing the beamsteering of the visible rays and the invisible rays such that an outline of a volume of the invisible rays is made visible by the visible rays.

In this embodiment, furthermore, the lighting control system 250 causes the luminaires 210, 211, and 212 to modulate their visible rays provided by their respective first source and their invisible rays provided by their respective second source, such that the source of origin of the respective rays can be identified. This means that it can be identified, which of the luminaires 210, 211, and 212 provided which rays. In other embodiments, the luminaire controller of a respective luminaire can be configured for modulating the visible rays provided by the first source and/or the invisible rays provided by the second source, such that the source of origin of the respective rays can be identified.

Window 260, in this embodiment, includes window blinds 262 which can be controlled by the lighting control system 250. The lighting control system 250 adjusts the window blinds 262 based on a radiant flux value of visible rays in the room 205. This allows an increase or reduction of radiant flux value of visible rays in the room 205. In other embodiments, the luminaire controller of a respective luminaire can be configured for adjusting the radiant flux value of visible rays in the space in which the luminaire is arranged based on a radiant flux value of visible rays in a space in which the luminaire is arranged and/or another sensor value.

In this embodiment, the directional characteristics of the visible rays and invisible rays can be made identical, i.e., the invisible rays and visible rays can be directed into the same direction from a respective luminaire, e.g., luminaire 212. This can allow to take glare effects into account for direct sight exposition. Therefore, the radiant flux value of the first source provided by the luminaire 212 allows to provide a related limiting radiant flux value for invisible rays from the same direction.

In addition, the lighting control system 250 may adjust visible light scenes allowing for an increased protection, e.g., by adjusting the wavelength or wavelength range of the visible rays, such as adjusting CCT whenever IR rays are activated for charging a user device, such as smart phone 221 or 222. This can reduce a risk that user 240 keeps looking for a prolonged time into the direction of the luminaire 212 as glare is not appreciated. Furthermore, sensitivity of eyes of the user 240 can be reduced by closing the iris due to visible rays impinging on them. This allows to also protect the eyes from invisible rays. Therefore, mid- and long-term exposure effects of IR within the eye can be reduced.

In other embodiments, in which UV rays are used, e.g., for UV disinfection, mid- and long-term exposure effects of UV within the eye can be reduced. In the following further embodiments of the lighting system are described.

In an embodiment, IR charging can be performed using directed IR beams generated from the IR rays provided by a second source of a respective luminaire.

In a further developed embodiment the lighting system senses the position of a user in the space in which the luminaire is arranged and limits the radiant flux value of the second source only if the occupant is hit by the invisible rays or is approaching them.

In a further developed embodiment, the luminaire can communicate a status information to the lighting control system, e.g., that the radiant flux value of the invisible rays has been limited. This can for example be used for extending a timespan for invisible ray production, e.g., for keeping charging or disinfection effect of the invisible rays constant.

In a further developed embodiment a camera based safety system analyses (FoV) of users and a relative distance between the user’s eye and the second source of a respective luminaire. Instead of the camera based safety system another image sensor based safety system may be provided. The camera based safety system may also provide a position of the luminaire in the room with respect to a user device, e.g., a smartphone lying on a 80 cm high table close by a third troffer from the right. In case that invisible rays are provided, a protection mode may be enabled in which the radiant flux value of the second source is limited based on the radiant flux value of the first source and a sensor value. The camera based safety system may be used to find possible unsafe reflections by detecting disturbing objects. The lighting system may then account for these reflections when limiting the radiant flux value of the second source. The camera based safety system may also predict the movement of the target object, for example a battery-operated BLE tag that is to be charged can be mounted on a fork lift. The camera based safety system may predict an immediate path of the forklift in a warehouse and provide the charging system with this information.

This may allow the charging system to find the moving target object and safely direct a high intensity charging beam to it.

The camera based system in conjunction with the general lighting may also be utilized for detecting transparent objects such as a window being opened or a glass plate entering the IR beam. The reflections from the IR beam from the transparent objects (5% Fresnel reflection) may lead to eye damage in long term exposure. Insertion of translucent objects are a key safety challenge for laser systems. The change of window position may be detected for instance by using RF sensing. In particular, disturbances in the wireless signal between two luminaires (e.g. Ivani ZigBee based RF sensing or Origin Wireless WiFi-based RF sensing) can be analysed. In a further developed embodiment the invisible and/or the visible rays can be modulated (coded light) in order to allow the camera based safety system to determine effects of every beam generated from the rays including any reflections and directly relate these to the source. In a further developed embodiment that includes modulated rays, a modulated light beam of safe intensity that has a bigger spot can be provided around a full intensity invisible beam. The radiant flux value of the second source can be reduced, when a user enters the bigger spot and before entering the full intensity beam.

In a different embodiment the camera based safety system can determine in which direction a user is looking and in particular, whether the user looks into the direction from which an IR beam of IR rays is heading. This can be performed by detecting glare effects caused by a visible light beam of visible rays which is provided by the same luminaire as the IR beam with the same directionality. In cases in which the user looks in the direction of the luminaire from which the IR beam and the visible light beam are provided, the pupil of the eye of the user becomes smaller and a fast blinking of the eyelid can be detected. This allows the camera based safety system to determine that the user looks into the direction from which the IR beam is heading. The radiant flux value of the second source can be reduced in response and/or the radiant flux value of the first source can be increased in response in order to improve eye safety of the user. For example, the second source can be shut down temporarily for the duration that the user looks into the direction of the luminaire. This can allow to reduce long-term exposure issues by IR beams with moderate laser power.

In a further developed embodiment the lighting system detects when the radiant flux value of the second source has been limited. The lighting control system can adjust the radiant flux value of the first source and/or a CCT of the first source for a currently provided lighting scene when the radiant flux value of the second source is limited to a value above a predetermined threshold radiant flux value.

In a different embodiment, the second source of a respective luminaire can include an IR unit including multiple laser bars each for providing a different wave length. If a presence value of 0 is detected indicating that no user is present, a first wave length with higher energy may be provided for high-speed battery charging and a second wave length with lower energy may be provided for data communication. If a presence value of 1 is determined, i.e., at least one user is present, the first wave length may be used for data communication and the second wave length may be used for charging. If high brightness of visible rays is provided in the space in which the respective luminaire is arranged, radiant flux value of the IR unit may be increased such that a first laser bar which provides the first wave length can act as both data communication transmitter and as IR battery charger.

In a different embodiment, the IR unit of a second source of a respective luminaire includes a first laser bar for providing IR rays and a second laser bar for providing UV rays. The UV laser bar is only used for Li-Fi communication to ensure connectivity if lots of moisture in the air. This can for example ensure Li-Fi connectivity while water sprinklers in a building are activated or if there is heavy rain in outdoor applications. Under normal dry conditions, IR rays are not absorbed by water and IR rays can be provided for performing Li-Fi communication.

In a different embodiment, the lighting system can include a user device. The user device can perform Li-Fi data communication with a respective luminaire arranged at a ceiling of a room in which the lighting system is arranged. The Li-Fi data communication can use a continuous data stream. The Li-Fi data communication can be performed by transmitting a Li-Fi beam of rays between the luminaire and the user device, e.g., a smart phone. If the Li-Fi beam, which is typically a low power IR beam, is interrupted, for example by a user getting into the LOS between the luminaire and the user device, the lighting system can disrupt or reduce the Li-Fi beam. The same is true in case that a high power IR charging beam is used for charging the user device at the same time. For example, an aperture can be increased and/or transmitted power can be reduced for eye safety reasons. Furthermore, the user can be provided with a signal generated by visible rays that the user has interrupted the beam, e.g. a red blinking light can be provided at the luminaire or any other signal.

In a different embodiment the sources of visible rays in the whole room in which the lighting system is arranged, are adjusted for providing a higher brightness and/or a higher CCT when radiant flux value of one or more second sources of respective luminaires are above a predetermined threshold radiant flux value. This will be done preferably keeping the lighting scene mostly while having an increased radiant flux value of sources of visible rays in order to have consistent lighting in the whole room. The sources of visible rays in the whole room may include a combination of daylight and artificial light. The daylight may be adjusted by changing a position of window blinds or by changing an amount of visible rays provided by skylight daylight systems.

In one embodiment, UV and IR units can be included in a combined manner in a lighting system. Invisible radiation can be used for Li-Fi as well as for charging and/or UV disinfection. The invisible rays may be beamsteered. In a further developed embodiment the lighting system may take the directionality of the rays into account for assessing a risk of eye hazards for users in the room in which the lighting system is arranged. Furthermore, beam steering can be provided in order to reduce the risk of eye hazards for users. In such a lighting system visible rays may be steered together with invisible rays in order to provide a direct feedback to a user of the availability of data communication or charging. Furthermore, the visible rays can be steered in order to protect the eyes of the user, e.g., using the reflex to close the eyes when visible rays are directed into the user’s eyes. Alternatively or additionally, the volume in which invisible rays are provided may be surrounded by visible rays in order to provide visual feedback to the user which volumes are dangerous and may provide eye hazards.

In one embodiment the lighting system is installed in an outdoor light pole. In this case, the lighting system may preferably provide UV rays. In other embodiments, UV rays may be combined with IR rays.

In another embodiment a respective luminaire provides invisible rays for disinfection functionality. A disinfection beam generated from the invisible rays, e.g. UV rays, may be steered. For instance, while a first target object may be in direct LOS of the respective luminaire and hence can be easily disinfected with UV rays, a second target object may be in non LOS. The second target object may thus only be reached via a reflection from a disturbing object, such as a reflecting object like a glass mirror or floor. The lighting system may apply a higher output power, e.g., higher radiant flux value, for the second path to the second target object as the reflection from the reflecting object will reduce the UV power delivered to the second target object.

In yet another embodiment, the lighting system provides a steerable beam and utilizes it to deliver light to plants within the room in which the lighting system is arranged. For instance, a scanning beam may be providing light of certain wavelength to each plant in the room, augmenting daylight and other artificial sources of rays, such as other luminaires in the room.

In a different embodiment, wireless charging is performed in a first volume, and a user is approaching the first volume from a second volume. The lighting control system may purposefully condition the eyes of the user with a glare bright light in the second volume to close the user’s pupil. Alternatively, the lighting control system can determine a lighting setting which the user was recently exposed to in the second volume and adjust a charging and/or Li-Fi beam accordingly. In an alternative embodiment, a beamsteered IR and/or UV ray providing second source of a respective luminaire adjusts its performed functions based on a light level and directionality of other sources of rays, e.g., all other sources of rays, in the room in which a lighting system including the respective luminaire is arranged. If a user selects during a time period tl a low-light condition for instance for temporarily performing CAD work on a computer screen, an IR charging beam power and therefore a corresponding radiant flux value of the second source, may be reduced accordingly to safeguard eye safety. The lighting system may also decide to utilize the beamsteered second source during this time period to not provide IR beams for IR charging, but to instead provide during time period tl low intensity growth light to potted plants. After a while, the plants may have received sufficient IR light and hence the lighting system may start to deliver during time period t2 fairly low intensity trickle charging to a smartphone. Once, the user increases the light level to high intensity white light in the room, the lighting system may increase during time period t3 the power of the IR beam to a higher level as in time period tl by increasing the radiant flux value of the second source. Alternatively, during period t3 it may be possible to concurrently perform Li-Fi communication and IR charging as sufficient power output is allowable without compromising eye safety. Alternatively, a first luminaire may provide Li-Fi communication to a first laptop and a second luminaire may provide Li-Fi communication to a smart phone and the first and second luminaire may team up to additionally charge the smart phone.

In an alternative embodiment, the lighting system may keep track of each user within an office in which the lighting system is arranged, including their respective recent exposures to IR and/or UV rays and their recent exposure to visible rays. For example, a first user may just have had a few seconds of high intensity white light and a second user may have been already sitting in the office for a prolonged time. The lighting system at first may operate at low intensity IR charging. The lighting system may then increase its intensity, e.g., by increasing a radiant flux value of the second source, upon identifying the specific user.

In a different embodiment, if very-far-field IR charging is required, for example for charging a smart phone lying far away from a respective luminaire providing IR rays, the radiant flux value of visible rays of all sources in the room in which the respective luminaire is arranged, may be increased in order to allow for a higher IR transmit power.

In yet another embodiment, a wave length or wave length range of a charging beam and its aperture may be adjusted based on a radiant flux value of the visible rays provided by sources of visible rays in the room in which a respective luminaire is arranged. Furthermore, these parameters may depend on a relative directionality of the visible rays compared to the directionality of the charging beam as well as on a dwell time of a user in the room. Preferably, for charging, an as small as possible dot is to be provided on a receiver photodiode of a smart phone to be charged in order to maximize a transmission efficiency. However, the smaller the dot, the more retina damage will result. Therefore, ensuring that a user does not look into the invisible rays is important to ensure eye safety.

In another embodiment, the lighting system reduces a radiant flux value of visible rays provided by sources in the room in which the lighting system is arranged when a second source of a respective luminaire of the lighting system is in a process of localizing a target object on which a task is to be performed, e.g., charging, data communication, disinfection, or providing specific wave length for plant growth. Providing a reduced radiant flux value of visible rays provided by the sources in the room allows to enhance the scanning process for localizing a target object, in particular, by improving a responsiveness of the target object to IR beams which are not perfectly aimed at the target object, as even with state-of-the-art filters some of the visible rays of the visible spectrum may affect the IR photo diode responsiveness.

In a further embodiment, a lighting system including an adjustable beam formed from visible rays is provided, for example an LCD-based beamsteering solution from LensVector. A lighting scene applied to the room in which the lighting system is arranged, may be adjusted based on a current position of a to-be-charged user device in the room in such a way that a two dimensional (2D) light distribution has high lux levels at the position of the user device. This can allow small eye openings and low retina damage of human users present in the room.

In an alternative embodiment, during a process of a luminaire-based IR beam searching/localizing a to-be-charged user device, e.g. smart phone, in a room in which the luminaire is arranged, a light intensity of visible rays may be lowered in order to increase the smart phone’s responsiveness. Upon localization of smart phone and during transmitting a high-powered IR beam for charging the smart phone, the light intensity of the visible rays may be increased, e.g., by increasing a radiant flux value of the first source or any other source of visible rays. This may allow an increased power transfer while ensuring eye safety. This embodiment may be combined with presence sensing in order to ensure non-hazardous radiation in rooms in which users are present. In another embodiment, the lighting system can be a wireless charging system that uses IR rays for wireless power transfer. The radiant flux values of visible and invisible rays can be controlled in order to increase eye safety.

In yet another embodiment, the lighting system can be a wireless charging system that modulates the IR beam and/or the visible rays in order to support camera based hazard pre-detection.

Fig. 3 shows an exemplary control curve 300 for determining a limiting radiant flux value 310 of the second source (vertical axis) in dependence of a radiant flux value 320 of the first source (horizontal axis).

The control curve 300 corresponds to a predetermined function for the limiting radiant flux value 310 of the second source. In this embodiment, the radiant flux value 320 of the first source corresponds to a dim percentage for the visible rays as input to the predetermined function.

The limiting radiant flux value 310 of the second source is zero before the radiant flux value 320 of the first source reaches a first threshold radiant flux value 301 of the first source. This means, that no invisible rays are provided from the second source when the first source provides a radiant flux value below the first threshold radiant flux value 301 of the first source. In this embodiment, the first threshold radiant flux value 301 corresponds to a dim percentage of the visible rays of 20 %.

The limiting radiant flux value 310 of the second source reaches a maximum when the radiant flux value 320 of the first source is above a second threshold radiant flux value 302 of the first source. In this embodiment, the second threshold radiant flux value 320 of the first source corresponds to a dim percentage of the visible rays of 80 %. The maximum of the radiant flux value 310 of the second source is 60 % of a maximal radiant flux value 310 that the second source could provide. This allows to ensure eye safety.

Fig. 4 shows schematically and exemplarily an embodiment of a method 400 for controlling a luminaire, e.g., the luminaire of Fig. 1 or one of the luminaires of Fig. 2. The luminaire comprises a first source of visible rays and a second source of invisible rays. The method can for example be used for improving performance of Li-Fi data communication,

UV disinfection, and/or IR charging.

In step 410, a sensor value is determined. In this embodiment, a presence value of a user is measured by a presence sensor. Therefore, a presence sensor measures whether a human user is present in a room in which the luminaire is arranged and provides a false value, e.g., 0, if no user is present and a true value, e.g., 1, if a user is present. In other embodiments, the sensor vale can be determined based on at least one of: a radiant flux value of visible rays in a space in which the luminaire is arranged, a presence value of a user, a position value of a user, a FoV value of a user, a characteristic of a user, an eye protection value of a user, a position value of a target object, a position value of a disturbing object, a predicted movement path of a user, a predicted movement path of a target object a predicted movement path of a disturbing object.

For example, in another embodiment, the radiant flux value of visible rays in a space in which the luminaire is arranged can be determined by considering the visible rays of all sources of visible rays. Therefore, an ambient light sensor can be used for measuring the radiant flux value of the visible rays in the space in which the luminaire is arranged. In this case step the following step 420 is optional, as the radiant flux value of the first source is already included and accounted for in the radiant flux value of the visible rays in the space in which the luminaire is arranged.

In step 420, a radiant flux value of the first source is determined. In this embodiment, the radiant flux value of the first source is determined by the first source. In other embodiments, the radiant flux value of the first source can also for example be determined by a sensor.

In step 430, a limiting radiant flux value of the second source is determined based on the radiant flux value of the first source and the presence value. If the presence value is 1, i.e., if a human user is present in the room, in this embodiment, the radiant flux value of the second source is limited based on control curve presented in Fig. 3. If no human user is present in the room, the radiant flux value of the second source is not limited based on the radiant flux value of the first source as eye safety is not an issue. Instead the radiant flux value of the second source can be set between zero and a maximal radiant flux value of the second source independent of the radiant flux value of the first source. In other embodiments, a limiting radiant flux value of the second source can also be determined based on a radiant flux value of the first source and another sensor value. For example, in the case that the radiant flux value of the visible rays in the space in which the luminaire is arranged is the sensor value, the radiant flux value of the second source may be higher than based on the radiant flux value of the first source alone, as additional sources of rays increase brightness and therefore also glare effect and closing of the eyelid of the user.

In step 440, the radiant flux value of the second source is limited based on the radiant flux value of the first source and the sensor value. Therefore, the radiant flux value of the second source is adjusted between zero and the limiting radiant flux value of the second source. In this embodiment, the radiant flux value of the second source is adjusted to the limiting radiant flux value of the second source in order to increase the performance of the method, e.g., UV disinfection, IR charging, and/or Li-Fi data communication.

In other embodiments, the radiant flux value of the second source may also be adjusted to another radiant flux value between zero and the limiting radiant flux value of the second source.

In yet other embodiments, the method can be used in a wireless charging system. The method can include user tracking in order to judge an actual eye sensitivity of a respective user. This can be used for controlling radiant flux values of visible rays and/or invisible rays in order to reduce eye hazards.

While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. For example, it is possible to operate the invention in an embodiment wherein charging, data communication, and/or disinfecting are combined. For example, IR charging, Li-Fi data communication and/or UV disinfection can be performed by a lighting system.

Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.

In the claims, the word “comprising” and “including” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality.

A single unit, processor, or device may fulfill the functions of several items recited in the claims. 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.

Operations like limiting a radiant flux value of the second source based on a radiant flux value of the first source and a sensor value determined by a sensor, determining the sensor value, et cetera performed by one or several units or devices can be performed by any other number of units or devices. These operations and/or the method can be implemented as program code means of a computer program and/or as dedicated hardware.

A computer program product may be stored/distributed on a suitable medium, such as an optical storage medium, or a solid-state medium, supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet, Ethernet, or other wired or wireless telecommunication systems.

Any reference signs in the claims should not be construed as limiting the scope.

The present invention relates to controlling luminaires which comprise a first source of visible rays and a second source of invisible rays. A radiant flux value of the second source is limited based on a radiant flux value of the first source and a sensor value determined by a sensor. The sensor value can be determined based on various measured values, including a radiant flux value of visible rays in a space in which the luminaire is arranged, a presence value of a user, a position value of a user, a field of view value of a user, and/or a position value of a target object or a disturbing object. This allows operating luminaires with increased radiant flux values of their second source while ensuring eye safety for human users.