Method for determining light settings of a light source configured to illuminate an individual - Patents.com

Abstract

The present invention relates to a method (300) for determining light settings of a light source configured to illuminate an individual, wherein the light settings of the light source comprise information about the circadian stimulation and color temperature of the light emitted by the light source. The method (300) includes determining a target light setting for the light source based on the individual's target light profile comprising time-resolved information about the circadian stimulus and color temperature of light to which the individual will be exposed and the individual's actual light profile comprising information about the circadian stimulus and color temperature of light to which the individual has been exposed (S302), where the target light setting comprises information about the circadian stimulus and color temperature of light to be emitted by the light source and is determined such that the actual light profile and the target light profile are aligned over time; comparing the target light setting to a light space (S304), where the light space is a range of circadian stimulus and color temperature of light that the light source can emit; in response to the target light setting being within the light space, setting the target light setting as the light setting of the light source (S306); in response to the target light setting being outside the light space, determining an acceptable light setting based on the target light setting and the light space such that the acceptable light setting is within the light space (S308); and setting the acceptable light setting as the light setting of the light source (S310).

Description

[Technical field]

[0001] The present invention relates to a method for determining light settings of a light source configured to illuminate an individual, and further to a control device and system thereof for determining light settings of a light source configured to illuminate an individual. [Background technology]

[0002] Chronobiology, the field of biology that studies timing (e.g., cyclical) processes and phenomena in living organisms, is becoming increasingly more important to understanding human physiology. For example, circadian rhythms are internal processes of organisms (e.g., humans) that regulate the sleep-wake cycle. Circadian rhythms typically repeat over a period of time slightly longer than 24 hours for most people. It is also known that this cycle can vary between different individuals. For example, some people are known to be "morning people," while others are "evening people." Thus, behavior at a given time for different individuals typically varies. This is usually referred to as a person's chronotype.

[0003] An important part of chronobiology is the study of the effects of light on living organisms. As is commonly known within the field, the circadian rhythm of an organism can be affected by light. Organisms, such as humans and animals, typically have cells in their eyes that respond to some wavelengths of light. For example, it has been discovered that exposing a person to bright light at night can extend the time it takes for the person to fall asleep. Recent studies have further discovered that light can affect a person's alertness and performance. In light of this, it becomes desirable to control the light to which a person is exposed according to a theoretically determined light dose, for example to improve a person's performance, well-being, or sleep cycle. However, in practice, there are limitations on how light can be adjusted. Summary of the Invention [Means for solving the problem]

[0004] As mentioned above, there are limitations on what light an individual can be exposed to. Therefore, due to different factors, it is not always possible to achieve the theoretically desired light dose for an individual. A limiting factor can be, for example, a limitation in the light source itself, i.e., what light spectrum or intensity the light source can achieve. Another example can be the activity of the individual, which in some way limits the possible spectrum or intensity of light.

[0005] The inventors of the present concept realize that by considering the circadian stimuli and color temperature of the light, as well as the light space that defines the possible light settings that can be achieved, an improved method of illuminating an individual with personalized light can be achieved.

[0006] According to a first aspect, a method is provided for determining light settings of a light source configured to illuminate an individual, wherein the light settings of the light source comprise information about a circadian stimulation and a color temperature of light emitted by the light source. The method includes the steps of determining a target light setting of the light source based on an individual's target light profile comprising time-resolved information about the circadian stimulus and color temperature of light to which the individual will be exposed and an individual's actual light profile comprising information about the circadian stimulus and color temperature of light to which the individual is exposed, wherein the target light setting comprises information about the circadian stimulus and color temperature of light to be emitted by the light source and is determined such that the actual light profile and the target light profile are aligned over time; comparing the target light setting to a light space, wherein the light space is a range of circadian stimulus and color temperature of light that the light source can emit; in response to the target light setting being within the light space, setting the target light setting as the light setting of the light source; in response to the target light setting being outside the light space, determining an acceptable light setting based on the target light setting and the light space, such that the acceptable light setting is within the light space; and setting the acceptable light setting as the light setting of the light source.

[0007] The expression "circadian stimulation" should be interpreted in the context of the present disclosure as the value of the effect of light on the circadian rhythm of an individual. In other words, this expression may represent to what extent light stimulates the circadian rhythm of an individual. As known in the art, light with high luminance or light with a blue spectrum component can have a greater effect on the circadian rhythm compared to light with low luminance or other colors. Circadian stimulation may be a measure of how effective the spectrally weighted irradiance is at the cornea of ​​an individual, from threshold to saturation. The circadian stimulation of light may be represented by a numerical value. The numerical value may be proportional to the degree of melatonin suppression of an individual after a period of exposure. The period of exposure may be, for example, 1 hour. Typically, a circadian stimulation value lower than 0.1 does not have a significant effect of melatonin suppression of an individual, while a circadian stimulation value higher than 0.3 has a significant effect. Thus, the numerical value of 0.1 may be considered as a threshold value. The range of circadian stimulation value can be 0-0.7. A circadian stimulation value of 0.7 can be associated with the maximum possible melatonin suppression of an individual. Thus, a circadian stimulation value of 0.7 can be considered as saturated. As a non-limiting example, it has been found that exposure to a circadian stimulation value of 0.3 or more in an individual's eye for at least one hour early in the day is effective for stimulating the circadian system and is associated with one or more of better sleep, improved mood, and improved behavior.

[0008] The color temperature of the light may be a correlated color temperature. By the expression "correlated color temperature" is intended herein the temperature of a hypothetical black-body radiator that emits light having the same color as the light in question. Depending on the spectral distribution of the light, a particular color temperature of the light may have different circadian stimuli.

[0009] The expression "target light profile" should be interpreted within the context of this disclosure as information regarding a preferred light dose or a preferred amount of light that a user should accumulate over time. The preferred light dose / preferred amount of light may vary by wavelength. The term "over time" may refer to a time period over which an individual should be exposed to a certain amount of light, such as a day, a week, a month, etc. The target light profile may be periodic with a 24-hour period. The target light profile may comprise information over a period of more than 24 hours.

[0010] The expression "actual light profile" should be interpreted within the context of this disclosure as information / data associated with the cumulative amount of light to which a user was exposed. The actual light profile may comprise information about the amount of light to which a user was exposed, as well as at which wavelengths, color temperatures, and / or circadian stimuli the user was exposed.

[0011] The determined light settings may be interpreted as specifying the properties (eg, intensity, color temperature, spectrum, etc.) of the light actually emitted by the light source.

[0012] The target light settings may be interpreted as representing how the light source should illuminate the individual to achieve the target light profile (i.e., so that the actual light profile and the target light profile are aligned over time). The target light settings may comprise time-resolved data. In other words, the target light settings may specify how the light source should illuminate the individual over time to achieve the target light profile. The target light settings may be interpreted as the target light profile translated into control settings of the light source.

[0013] A light space may be interpreted as a set of possible light settings of a light source. Possible light settings may be light settings that the light source actually supports. Thus, a light space may represent the hardware limitations of the light source.

[0014] Comparing the target light setting to the light space can be interpreted as determining whether the circadian stimuli of the target light setting are within the range of the circadian stimuli of the light space, and determining whether the color temperature of the target light setting is within the range of the color temperatures of the light space.

[0015] By the expression "acceptable light setting" is intended herein a light setting of a light source that is within the light space and is selected with the target light profile in mind. An acceptable light setting may be a light setting that is as close as possible to the target light setting while still being within the light space.

[0016] A possible related advantage of the concept of the present invention is that if the target light setting is not achievable, the acceptable light setting can be determined as a way to find a compromise between the light space and the target light setting. In other words, the acceptable light setting can be a compromise between the desired light setting of the light source and the light setting that the light source actually supports. This allows the circadian rhythm of an individual to be positively stimulated (e.g., in the sense of improving well-being or performance) in more situations. Alternatively, if the target light setting is achievable (i.e., within the light space), the target light setting can be directly set as the light setting without the need for any additional calculations.

[0017] To obtain high circadian stimulation, the illuminance of the light can typically be increased, i.e., the brightness of the light can be increased. However, increasing the brightness typically means increasing the power consumption of the light source. Therefore, the concept of the present invention is advantageous in that it allows a change in color temperature instead of illuminance to obtain different circadian stimulation, even in situations where the adjustment of color temperature may be limited.

[0018] The method may further include determining an overlap between a range of circadian stimuli and a range of color temperatures of light that the light source can emit and at least one range of circadian stimuli and at least one range of color temperatures of light that can be enabled by at least one current activity of the individual, and the light space may be the determined overlap.

[0019] In other words, the overlap may represent the range of circadian stimuli and the range of color temperatures that both the light source and the current activity allow. Thus, the light space may be the possible light settings that are both what the light source can achieve and what the current activity allows.

[0020] By "current activity" is intended herein any possible activity of an individual that may limit how a light may be adjusted. It may be, for example, a certain task that an individual is performing or how an individual is using a light source. Thus, a current activity limit may be a non-hardware related limit.

[0021] A possible related advantage is that the light settings can be determined further based on the current activity of the individual. This can enable an improved method of determining light settings, since there can be more than just hardware-related limitations on how the light source illuminating the individual can be controlled. The improved method can be improved in the sense that the determined light settings allow the light to be adapted for the individual's target light profile without interfering with the individual's current activity. At the same time, it can allow the light to be adjusted for the target light profile even when there are limitations, thereby allowing a better alignment of the target light profile and the actual light profile. In other words, despite the current activity, the light settings can be determined in such a way that they can contribute in a positive direction towards the individual's well-being.

[0022] The method may further include determining a first overlap between a range of circadian stimuli and color temperatures of light that the light source can emit and a range of circadian stimuli and color temperatures of light enabled by a first current activity of the individual, where the first current activity may be associated with a first priority, and determining a second overlap between the range of circadian stimuli and color temperatures of light that the light source can emit and a range of circadian stimuli and color temperatures of light enabled by a second current activity of the individual, where the second current activity may be associated with a second priority, where the light space may be the first overlap if the first priority is higher than the second priority and the second overlap if the second priority is higher than the first priority.

[0023] A possible related advantage is that if two opposing activities are performed simultaneously, the light settings can be determined based on the most important activity.

[0024] Priority may be viewed as a measure of how important the current activity is. More specifically, priority may be a measure of how important it is to comply with the restrictions in light that the activity entails.

[0025] The act of determining the target light setting may be further based on the range of circadian stimuli and the range of color temperatures of light allowed by the individual's future activities.

[0026] Taking future limitations into account may allow target light settings to be determined in advance that may compensate for future limitations of an individual's exposure.

[0027] The act of determining an acceptable light setting may include, if a circadian stimulus of the target light setting is within a range of circadian stimulus of the light space and a color temperature of the target light setting is outside a range of color temperatures of the light space, selecting a color temperature within the color temperature range of the light space that achieves a circadian stimulation of the target light setting; and setting the circadian stimulus of the target light setting and the selected color temperature as the acceptable light setting; If the circadian stimulus of the target light setting is outside the range of the circadian stimulus of the light space, and the color temperature of the target light setting is within the range of the color temperature of the light space, selecting a circadian stimulus within the range of circadian stimuli of the light space that achieves a color temperature of the target light setting; and setting the color temperature of the selected circadian stimulus and target light setting as the acceptable light setting; or If the circadian stimulus of the target light setting is within the range of the circadian stimulus of the light space, and the color temperature of the target light setting is within the range of the color temperature of the light space, selecting a color temperature within the color temperature range of the light space that achieves a circadian stimulation of the target light setting; and setting the circadian stimulus of the target light setting and the selected color temperature as the acceptable light setting; or selecting a circadian stimulus within the range of circadian stimuli of the light space that achieves a color temperature of the target light setting; and The step of setting the selected circadian stimulus and color temperature of the target light setting as the acceptable light setting may be included.

[0028] The operation of determining the acceptable light setting may include selecting a color temperature and a circadian stimulus within the light space that minimizes the difference between the selected color temperature and the color temperature of the target light setting, and the difference between the selected circadian stimulus and the circadian stimulus of the target light setting, and setting the selected color temperature and the selected circadian stimulus as the acceptable light setting.

[0029] A possible related advantage is that a light setting may be selected that is as close as possible to the target light setting, thereby minimizing differences in the light settings.

[0030] The light source may be an electronic display.

[0031] The method may further include controlling the light source according to the light settings such that the individual's actual light profile may be aligned with the individual's target light profile over time.

[0032] According to a second aspect, there is provided a control device for determining a light setting of a light source configured to illuminate an individual, wherein the light setting of the light source comprises information about a circadian stimulus and a color temperature of light emitted by the light source. The control device comprises a first determination function configured to: determine a target light setting of the light source based on a target light profile of the individual comprising time-resolved information about the circadian stimulus and color temperature of light to which the individual will be exposed and an actual light profile of the individual comprising information about the circadian stimulus and color temperature of light to which the individual has been exposed, the target light setting comprising information about the circadian stimulus and color temperature of light to be emitted by the light source, and determined such that the actual light profile and the target light profile are aligned over time; and compare the target light setting to a light space, the light setting being determined based on a target light profile of the individual comprising time-resolved information about the circadian stimulus and color temperature of light to which the individual will be exposed, the target light setting being determined such that the actual light profile and the target light profile are aligned over time; The space may be a range of circadian stimuli and a range of color temperatures of light that the light source is capable of emitting, a setting function configured to set the target light setting as the light setting of the light source in response to the target light setting being within the light space, and a second determination function configured to determine an acceptable light setting based on the target light setting and the light space in response to the target light setting being outside the light space, such that the acceptable light setting is within the light space, and the setting function may be further configured to set the acceptable light setting as the light setting of the light source in response to the target light setting being outside the light space.

[0033] The circuitry may further be configured to perform a third determination function configured to determine an overlap between a range of circadian stimuli and a range of color temperatures of light that the light source can emit and at least one range of circadian stimuli and at least one range of color temperatures of light enabled by at least one current activity of the individual, and the light space may be the determined overlap.

[0034] The circuit may be further configured to perform a fourth determination function, the fourth determination function being configured to determine a first overlap between a range of circadian stimuli and a range of color temperatures of light that the light source can emit and a range of circadian stimuli and a range of color temperatures of light enabled by a first current activity of the individual, where the first current activity may be associated with a first priority, and to determine a second overlap between the range of circadian stimuli and a range of color temperatures of light that the light source can emit and a range of circadian stimuli and a range of color temperatures of light enabled by a second current activity of the individual, where the second current activity may be associated with a second priority, where the light space may be the first overlap if the first priority is higher than the second priority, and the second overlap if the second priority is higher than the first priority.

[0035] The first determination function may be further configured to determine the target light setting further based on a range of circadian stimuli and a range of color temperatures of light allowed by the individual's future activities.

[0036] The second decision function is If the circadian stimulus of the target light setting is within the range of the circadian stimulus of the light space, and the color temperature of the target light setting is outside the range of the color temperature of the light space, Selecting a color temperature within the color temperature range of the light space that achieves the circadian stimulation of the target light setting; and Setting the circadian stimulus of the target light setting and the selected color temperature as the acceptable light setting; If the circadian stimulus of the target light setting is outside the range of the circadian stimulus of the light space, and the color temperature of the target light setting is within the range of the color temperature of the light space, selecting a circadian stimulus that achieves a color temperature of the target light setting within the range of circadian stimuli of the light space; and Setting the color temperature of the selected circadian stimulus and target light setting as the acceptable light setting; or If the circadian stimulus of the target light setting is within the range of the circadian stimulus of the light space, and the color temperature of the target light setting is within the range of the color temperature of the light space, Selecting a color temperature within the color temperature range of the light space that achieves the circadian stimulation of the target light setting; and Setting the circadian stimulus of the target light setting and the selected color temperature as the acceptable light setting; or selecting a circadian stimulus that achieves a color temperature of the target light setting within the range of circadian stimuli of the light space; and Setting the color temperature of the selected circadian stimulus and target light setting as the acceptable light setting. The signal processing unit may be configured to perform the following steps.

[0037] The second decision function may be configured to select a color temperature and a circadian stimulus within the light space that minimizes a difference between the selected color temperature and the color temperature of the target light setting and a difference between the selected circadian stimulus and the circadian stimulus of the target light setting, and to set the selected color temperature and the selected circadian stimulus as the acceptable light setting.

[0038] The light source may be an electronic display.

[0039] The circuitry may be further configured to perform a control function configured to control the light source according to the light settings such that an individual's actual light profile may be aligned with the individual's target light profile over time.

[0040] The above-mentioned features of the first aspect also apply to this second aspect, where applicable, and in order to avoid excessive repetition, reference is made to the above.

[0041] According to a third aspect, there is provided a non-transitory computer readable recording medium having program code portions recorded thereon which, when executed on a device having processing capability, performs the method according to the first aspect.

[0042] The above mentioned features of the first and second aspects also apply to this third aspect, where applicable, and in order to avoid excessive repetition, reference is made to the above.

[0043] The programs may be downloadable from an application provisioning service to a device having processing capabilities.

[0044] According to a fourth aspect, there is provided a system for determining light settings of a light source configured to illuminate an individual, wherein the light settings of the light source may comprise information about a circadian stimulus and a color temperature of light emitted by the light source. The system comprises a control device according to the second aspect and a light source communicatively connected to the control device and configured to illuminate the individual according to the light settings such that an accumulated amount of light received by the individual is aligned with a target light profile.

[0045] The above-mentioned features of the first, second and third aspects, where applicable, also apply to this fourth aspect, and in order to avoid excessive repetition, reference is made to the above.

[0046] Further scope of applicability of the present disclosure will become apparent from the following detailed description. It should be understood, however, that the detailed description and specific examples, while indicating preferred variations of the inventive concept, are given by way of example only, since various changes and modifications within the scope of the inventive concept will become apparent to those skilled in the art from this detailed description.

[0047] Thus, it is to be understood that the inventive concept is not limited to the particular steps of the described methods or component parts of the described systems, as such methods and systems may vary. It is also to be understood that the terminology used herein is merely for the purpose of describing particular embodiments and is not intended to be limiting. It should be noted that, as used in the specification and the appended claims, the articles "a," "an," "the," and "said" are intended to mean that there are one or more of an element, unless the context clearly dictates otherwise. Thus, for example, reference to "a device" or "the device" may include several devices, and the like. Furthermore, the words "comprising," "including," "containing," and similar expressions do not exclude other elements or steps.

[0048] These and other aspects of the inventive concept will now be described in more detail with reference to the accompanying drawings, which show variations of the inventive concept, and which should not be considered as limiting the invention to the specific variations, but are instead used to explain and understand the inventive concept.

[0049] As shown in the figures, the sizes of layers and regions are exaggerated for illustrative purposes and, thus, are provided to illustrate schematic configurations of variations of the inventive concepts. Like reference numerals refer to like elements throughout. [Brief description of the drawings]

[0050] [Figure 1] FIG. 1 illustrates a schematic diagram of a system for determining light settings for a light source configured to illuminate an individual. [Diagram 2] FIG. 1 is a schematic representation of a control device for determining light settings of a light source configured to illuminate an individual. [Figure 3A]4 is a flow chart illustrating method steps for determining light settings for a light source configured to illuminate an individual. [Figure 3B] 4 is a flow chart illustrating method steps for determining light settings for a light source configured to illuminate an individual. [Figure 3C] 4 is a flow chart illustrating method steps for determining light settings for a light source configured to illuminate an individual. [Figure 3D] 4 is a flow chart illustrating method steps for determining light settings for a light source configured to illuminate an individual. [Figure 4A] 4A-4C show different examples of light spaces to illustrate the relationship between circadian stimuli and color temperature described with respect to FIGS. 1-3. [Figure 4B] 4A-4C show different examples of light spaces to illustrate the relationship between circadian stimuli and color temperature described with respect to FIGS. 1-3. [Figure 4C] 4A-4C show different examples of light spaces to illustrate the relationship between circadian stimuli and color temperature described with respect to FIGS. 1-3. [Figure 4D] 4A-4C show different examples of light spaces to illustrate the relationship between circadian stimuli and color temperature described with respect to FIGS. 1-3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0051] The inventive concept will now be described more fully hereinafter with reference to the accompanying drawings, in which presently preferred versions of the inventive concept are shown. However, the inventive concept may be embodied in many different forms and should not be construed as limited to the variations set forth herein, but rather, these variations are provided for the sake of thoroughness and completeness, and to fully convey the scope of the inventive concept to those skilled in the art.

[0052] A method for determining light settings of a light source configured to illuminate an individual, and a control device and system thereof, will now be described with reference to Figures 1 to 4D.

[0053] 1 illustrates a system 100 for determining light settings of a light source 102 configured to illuminate an individual 104 in accordance with the concepts of the present invention. The system 100 may be a light control system. An example of such a light control system may be the BioCentric Lighting™ system provided by the applicant. The system 100 comprises a control device 200. The control device 200 is configured to perform control of the system 100. The control device 200 is further described with respect to FIG.

[0054] The system 100 further comprises a light source 102 configured to illuminate the individual. The light source 102 may be any type of electrical light source, such as a lamp as described herein. The light source 102 may comprise one or more lighting fixtures, such as a lamp. The system 100 may further comprise a plurality of light sources configured to illuminate the individual 104. Alternatively, or in combination, the light source 102 may be an electronic display. The electronic display may be a display of the electronic device 106. The electronic device 106 may be, for example, a mobile phone (as described herein), a tablet, a computer monitor, a television, smart glasses, etc. Although shown as separate devices, the light source 102 and the control device 200 may be one and the same device.

[0055] The light source 102 is communicatively connected to the control device 200. The light source 102 may be communicatively connected to the control device 200 via a hardwired connection and / or a wireless connection. A hardwired connection may be, for example, a connection via USB, Ethernet, Firewire, power line (using power line communication, PLC), etc. A wireless connection may be, for example, a connection via Wi-Fi, Li-Fi, NFC, Bluetooth, etc.

[0056] The control device 200 is configured to control the light sources 102 to illuminate the individual 104 based on a target light profile associated with the individual 104. The light sources 102 are controlled according to light settings such that the illumination of the individual 104 accumulates to an amount of light that is consistent with the target light profile. The target light profile may comprise information about a preferred light dose to which the individual should be exposed. Thus, controlling the light sources based on the target light profile may be interpreted as adjusting the light sources to emit the light to which the individual should be exposed, thus achieving the target light profile. If the system 100 comprises multiple light sources, the control device 200 may be configured to control the multiple light sources such that the illumination of the individual 104 accumulates to an amount of light that is consistent with the target light profile.

[0057] The light settings may be determined by the control device 200.

[0058] Individual 104 is shown here in dashed lines to indicate that the individual is not part of the system 100 .

[0059] FIG. 2 is a schematic diagram of a control device 200 as described above with respect to FIG.

[0060] The control device 200 comprises a circuit 202. The circuit 202 may physically comprise one single circuit device. Alternatively, the circuit 202 may be distributed across several circuit devices. As shown in the example of FIG. 2, the control device 200 may further comprise a transceiver 206 and a memory 208. The circuit 202 is communicatively connected to the transceiver 206 and the memory 208. The circuit 202 may comprise a data bus (not shown in FIG. 2), and the circuit 202 may communicate with the transceiver 206 and / or the memory 208 via the data bus.

[0061] The circuit 202 may be configured to perform overall control of the functions and operations of the control device 200. The circuit 202 may include a processor 204, such as a central processing unit (CPU), microcontroller, or microprocessor. The processor 204 may be configured to execute program code stored in a memory 208 to perform the functions and operations of the control device 200. The circuit 202 is configured to perform a first determination function 210, a comparison function 212, a setting function 214, and a second determination function 216. The circuit 202 may be further configured to perform one or more of a third determination function 218, a fourth determination function 220, and a control function 222. One or more of the first determination function 210, the second determination function 216, the third determination function 218, and the fourth determination function 220 may be implemented as a single determination function.

[0062] The transceiver 206 may be configured to allow the control device 200 to communicate with other devices. The transceiver 206 may both transmit data from and receive data to the control device 200. For example, the control device 200 may collect data about an individual, such as the individual's calendar schedule or future planned activities. This type of information may be collected, for example, from a remote server, or from the individual's user device, such as the individual's phone. Additionally, a user may input information into the control device. Although not explicitly shown in FIG. 2, the control device 200 may include input devices, such as one or more of a keyboard, a mouse, and a touch screen. Input from the user may be used, for example, in determining light settings or to obtain information about the individual's current and / or future activities. By including input from the user as feedback to the method, system, or control device, even further improved light settings are provided. The control device 200 may communicate with the light source 102 via the transceiver 206.

[0063] The memory 208 may be a non-transitory computer-readable storage medium. The memory 208 may comprise one or more of a buffer, a flash memory, a hard drive, a removable media, a volatile memory, a non-volatile memory, a random access memory (RAM), or another suitable device. In a typical arrangement, the memory 208 may include a non-volatile memory for long-term data storage and a volatile memory that serves as a system memory for the control device 200. The memory 208 may exchange data with the circuit 202 over a data bus. There may also be associated control lines and address buses between the memory 208 and the circuit 202.

[0064] The functions and operations of the control device 200 may be implemented in the form of executable logic routines (e.g., lines of code, software programs, etc.) stored on a non-transitory computer-readable recording medium (e.g., memory 208) of the control device 200 and executed by the circuit 202 (e.g., using the processor 204). In other words, when the circuit 202 is described as being configured to perform a particular function, the processor 204 of the circuit 202 may be configured to execute program code portions stored on the memory 208, where the stored program code portions correspond to the particular function. Furthermore, the functions and operations of the circuit 202 may be standalone software applications or may form part of a software application that performs additional tasks related to the circuit 202. The functions and operations described may be considered to be methods that a corresponding device is configured to perform, such as the methods described below with respect to Figures 3A-3D. Also, while the functions and operations described may be implemented in software, such functions may also be performed via dedicated hardware or firmware, or some combination of one or more of hardware, firmware, and software. The following functions may be stored on a non-transitory computer-readable recording medium.

[0065] The first determination function 210 is configured to determine a target light setting of the light source based on the target light profile of the individual and the actual light profile of the individual. The target light setting is determined such that the actual light profile and the target light profile are aligned over time when the light source illuminates the individual according to the target light setting. The target light profile comprises time-resolved information about the circadian stimulus and color temperature of the light to which the individual will be exposed. The actual light profile of the individual comprises information about the circadian stimulus and color temperature of the light to which the individual is exposed. The target light setting comprises information about the circadian stimulus and color temperature of the light to which the light source will be emitted. As an example, based on a comparison between the light to which the individual is exposed (i.e., according to the actual light profile) and the target light profile, it may be concluded that the individual is not exposed to enough blue light. In this case, the target light setting may be determined such that the individual is exposed to more blue light.

[0066] A target light setting may be interpreted as a desired light setting, as opposed to a light setting to be determined by the method of the inventive concept, which may be interpreted as the actual light setting used to control a light source.

[0067] The comparison function 212 is configured to compare the target light setting to a light space. The light space is a range of circadian stimuli and a range of color temperatures of light that the light source can emit. Comparing the target light setting to the light space may include determining whether the circadian stimuli of the target light setting are within the range of circadian stimuli of the light space and determining whether the color temperature of the target light setting is within the range of color temperatures of the light space. In addition, it may be determined how far the circadian stimuli and / or color temperature of the target light setting are from the corresponding ranges of the light space.

[0068] The setting functionality 214 is configured to set the target light setting as the light setting of the light source in response to the target light setting being within the light space. In other words, when the target light setting is within the light space, the target light setting may be used as the light setting for the light source.

[0069] The second determination function 216 is configured to determine an acceptable light setting based on the target light setting and the light space in response to the target light setting being outside the light space. The acceptable light setting is determined to be within the light space. The acceptable light setting may be determined to be within the light space and as close as possible to the target light setting. Different methods for determining the acceptable light setting are described below with respect to the description of Figures 4A-4B. In Figures 4C-4D, different methods of determining the light space are described.

[0070] The setting functionality 214 is further configured to set the acceptable light setting as the light setting of the light source in response to the target light setting being outside the light space.

[0071] The third determination function 218 may be configured to determine an overlap between a range of circadian stimuli and a range of color temperatures of light that the light source can emit and at least one range of circadian stimuli and at least one range of color temperatures of light that are enabled by at least one current activity of the individual. The light space may be the determined overlap. In other words, the overlap may be the range of circadian stimuli and the range of color temperatures that are enabled by both the light source and the at least one activity.

[0072] An individual's current activity can be any type of activity that limits what light can be emitted. For example, an individual may be reading or working. This may require bright light, i.e., light that is more oriented toward a spectrum of high intensity and cooler temperatures. In another example, an individual may be eating at night and desire a dimmer light. This may mean light with a warmer color temperature and lower intensity. It should be understood that the above activities are only examples and that an activity may require high intensity and warmer color temperature, or low intensity and cooler color temperature.

[0073] If the light source is an electronic display, the current activity may be related to what content is shown on the display and / or what application is running, since this may limit how the light emitted from the display may be adjusted. For example, some applications may require specific color settings, such as video games (which may require a specific dark or light background). Other applications may require image reproduction as accurate as possible (e.g., video or photo editing applications). Thus, these types of applications may limit how the light emitted from the display may be adjusted. The current activity may be determined by the control device 200 by obtaining information about what applications are running on the device associated with the electronic display. The range of circadian stimuli and the range of color temperatures allowed by an application (i.e., the light space of the application) may be pre-determined and stored in the control device 200 (e.g., in a database stored on the memory 208).

[0074] The fourth determining function 220 may be configured to determine a first overlap between a range of circadian stimuli and a range of color temperatures of light that the light source may emit and a range of circadian stimuli and a range of color temperatures of light that are enabled by a first current activity of the individual, where the first current activity may be associated with a first priority. The fourth determining function 220 may be further configured to determine a second overlap between a range of circadian stimuli and a range of color temperatures of light that the light source may emit and a range of circadian stimuli and a range of color temperatures of light that are enabled by a second current activity of the individual, where the second current activity may be associated with a second priority. The light space may be a first overlap if the first priority is higher than the second priority, and a second overlap if the second priority is higher than the first priority. Determining which priority is higher than the other may be performed by the fourth determining function 220. Examples of how the overlap may be determined are provided with respect to FIGS. 4A-4D. The priority associated with an activity may depend on the time of day that the activity is performed.

[0075] The first determination function 210 may be further configured to determine the target light setting further based on the range of circadian stimulation and the range of color temperature of the light enabled by the individual's future activity. The range of circadian stimulation and the range of color temperature of the light enabled by the future activity may be the light space of the future activity. The future activity may be a planned activity. Such future activity information may be retrieved from a calendar associated with the individual. The future activity may be predicted based on the individual's typical behavioral pattern. For example, if the individual typically watches TV during a certain time at night, the act of watching TV may be the individual's predicted future activity during the certain time. It should be understood that artificial intelligence (AI) and / or machine learning may be used to predict the future activity. When determining the target light setting based on the individual's future activity, the target light setting may be determined in advance to compensate for future limitations in light adjustment. For example, if the future activity requires light that also provides high stimulation to the individual later in the day, the target light setting may be adapted to understimulate the individual prior to the planned activity. In other words, the light settings are determined to ensure that the actual light profile and the target light profile will be aligned later in the day. If instead the future activity requires light that provides low stimulation of the individual, e.g., low circadian stimulation, the target light settings may be adapted to overstimulate the individual prior to the planned activity. In other words, the light settings are determined so that the actual light profile is closer to being aligned with the target light profile earlier in the day than if the future activity were not to be performed.

[0076] The second determination function 216 may be configured to select a color temperature within the range of color temperatures of the light space that achieves the circadian stimulation of the target light setting, if the circadian stimulation of the target light setting is within the range of circadian stimulation of the light space and the color temperature of the target light setting is outside the range of color temperatures of the light space, and set the circadian stimulation of the target light setting and the selected color temperature as the acceptable light setting. If the color temperature of the target light setting is outside the range of color temperatures of the light space, a color temperature within the range of color temperatures of the light space may be selected such that the difference between the selected color temperature and the color temperature of the target light setting is minimized. The selected color temperature may be one of a set of color temperatures within the range of color temperatures of the light space that achieves the circadian stimulation of the target light setting. How the range of circadian stimulation and the range of color temperatures may relate to each other is further described with respect to FIGS. 4A-4D.

[0077] The second determination function 216 may be configured to select a circadian stimulus that achieves the color temperature of the target light setting within the range of the circadian stimulus of the light space and set the selected circadian stimulus and the color temperature of the target light setting as an acceptable light setting if the circadian stimulus of the target light setting is outside the range of the circadian stimulus of the light space and the color temperature of the target light setting is within the range of the color temperature of the light space. If the circadian stimulus of the target light setting is outside the range of the circadian stimulus of the light space, a circadian stimulus within the range of the circadian stimulus of the light space may be selected such that the difference between the selected circadian stimulus and the circadian stimulus of the target light setting is minimized. The selected circadian stimulus may be one of a set of circadian stimuli within the range of the circadian stimulus of the light space that achieves the color temperature of the target light setting.

[0078] The second determination function 216 may be configured to select a color temperature within the range of color temperatures of the light space that achieves the circadian stimulus of the target light setting, if the circadian stimulus of the target light setting is within the range of the circadian stimulus of the light space and the color temperature of the target light setting is within the range of color temperatures of the light space, and set the circadian stimulus of the target light setting and the selected color temperature as the acceptable light setting. Alternatively, the second determination function 216 may be configured to select a circadian stimulus that achieves the color temperature of the target light setting within the range of the circadian stimulus of the light space, and set the selected circadian stimulus and the color temperature of the target light setting as the acceptable light setting. In this case, if the target light setting (i.e., the combination of the circadian stimulus and color temperature of the target light setting) is outside the light space, but the circadian stimulus of the target light setting is alone within the range of the circadian stimulus of the light space and the color temperature of the target light setting is alone within the range of the color temperatures of the light space, either the circadian stimulus or the color temperature of the target light setting may be set as the circadian stimulus or color temperature of the target light setting, respectively. In such cases, the other of the circadian stimulus and color temperature may be selected from a range of circadian stimuli or color temperatures of the light space. The other of the circadian stimulus and color temperature may be selected such that a difference between the selected circadian stimulus or color temperature and the circadian stimulus or color temperature of the target light setting is minimized.

[0079] The second decision function 216 can be configured to select a color temperature and a circadian stimulus within the light space that minimizes the difference between the selected color temperature and the color temperature of the target light setting and the difference between the selected circadian stimulus and the circadian stimulus of the target light setting, and to set the selected color temperature and the selected circadian stimulus as the acceptable light setting.

[0080] The control function 222 may be configured to control the light source according to the light settings such that the individual's actual light profile is aligned with the individual's target light profile over time. The control device 200 may be configured to determine the actual light profile, i.e., the accumulated amount of light received by the individual. For example, the control device 200 may be in communication with a light sensor configured to determine and / or estimate the individual's exposure. The light sensor may be worn by the individual. The light sensor may be located at a location where the light source is configured to illuminate. Alternatively or additionally, the light source may be configured to communicate a current light output to the control device 200, and the circuitry 202 may be configured to determine and / or estimate an accumulated amount of light received by the individual by accumulating the current light output over time. Alternatively or additionally, the control device 200 may be configured to determine and / or estimate a current light output from the light source from a light setting sent to the light source by the circuitry 202, and the circuitry 202 may be configured to determine and / or estimate an accumulated amount of light received by the individual by accumulating the current light output over time.

[0081] 3A-3D are flow charts illustrating steps of a method 300 for determining light settings of a light source configured to illuminate an individual, where the light settings of the light source comprise information about the circadian stimulation and color temperature of the light emitted by the light source. In more detail, FIGS. 3A and 3B illustrate the method 300 with different optional steps. FIGS. 3C and 3D illustrate different optional sub-steps to operation S308 of determining acceptable light settings, as described further below.

[0082] In the following the different steps are explained in more detail. Although shown in a particular order, the steps of method 300 may be performed in any suitable order, in parallel as well as multiple times.

[0083] A target light setting of the light source is determined in S302 based on the target light profile of the individual and the actual light profile of the individual. The target light profile may comprise time-resolved information about the circadian stimulus and color temperature of the light to which the individual will be exposed. The actual light profile of the individual may comprise information about the circadian stimulus and color temperature of the light to which the individual has been exposed. The target light setting may comprise information about the circadian stimulus and color temperature of the light to be emitted by the light source. The target light setting is determined such that the actual light profile and the target light profile are aligned over time.

[0084] The light source may be an electronic display.

[0085] The target light setting is compared to a light space in S304. The light space may be a range of circadian stimuli and color temperatures of light that the light source is capable of emitting.

[0086] In response to the target light setting being within the light space, the target light setting is set as the light setting of the light source, at S306.

[0087] In response to the target light setting being outside the light space, an acceptable light setting is determined based on the target light setting and the light space, in S308, such that the acceptable light setting is within the light space, and the acceptable light setting is set as the light setting of the light source, in S310.

[0088] An overlap between a range of circadian stimuli and a range of color temperatures of light that the light source can emit and at least one range of circadian stimuli and at least one range of color temperatures of light enabled by at least one current activity of the individual can be determined in S314. A light space can be the determined overlap.

[0089] A first overlap between the range of circadian stimuli and color temperatures of light that the light source can emit and the range of circadian stimuli and color temperatures of light enabled by a first current activity of the individual may be determined in S316. The first current activity may be associated with a first priority. A second overlap between the range of circadian stimuli and color temperatures of light that the light source can emit and the range of circadian stimuli and color temperatures of light enabled by a second current activity of the individual may be determined in S318. The second current activity may be associated with a second priority. The light space may be a first overlap if the first priority is higher than the second priority, and may be a second overlap if the second priority is higher than the first priority.

[0090] Determining the target light setting in S302 may be further based on a range of circadian stimuli and a range of color temperatures of light allowed by the individual's future activities.

[0091] Determining the acceptable light settings in S308 may include, if the circadian stimulus of the target light setting is within the range of the circadian stimulus of the light space and the color temperature of the target light setting is outside the range of color temperatures of the light space, selecting a color temperature within the range of color temperatures of the light space that achieves the circadian stimulus of the target light setting in S320, and setting the circadian stimulus of the target light setting and the selected color temperature as the acceptable light setting in S322.

[0092] Determining the acceptable light settings in S308 may include, if the circadian stimulus of the target light setting is outside the range of the circadian stimulus of the light space and the color temperature of the target light setting is within the range of the color temperatures of the light space, selecting a circadian stimulus that achieves a color temperature of the target light setting within the range of the circadian stimulus of the light space in S324, and setting the selected circadian stimulus and color temperature of the target light setting as the acceptable light setting in S326.

[0093] Determining the acceptable light settings in S308 may include, if the circadian stimulus of the target light setting is within the range of the circadian stimulus of the light space and the color temperature of the target light setting is within the range of the color temperatures of the light space, selecting a color temperature within the range of the color temperatures of the light space that achieves the circadian stimulus of the target light setting in S328 and setting the circadian stimulus of the target light setting and the selected color temperature as the acceptable light setting in S330, or selecting a circadian stimulus that achieves the color temperature of the target light setting within the range of the circadian stimulus of the light space in S332 and setting the selected circadian stimulus and the color temperature of the target light setting as the acceptable light setting in S334.

[0094] Determining the acceptable light settings in S308 may include selecting a color temperature and a circadian stimulus in the light space that minimizes a difference between the selected color temperature and the color temperature of the target light setting, and a difference between the selected circadian stimulus and the circadian stimulus of the target light setting, in S336, and setting the selected color temperature and the selected circadian stimulus as the acceptable light setting, in S338.

[0095] The light source may be controlled in S312 according to the light settings such that the individual's actual light profile is aligned with the individual's target light profile over time.

[0096] 4A-4D particularly show how acceptable light settings can be determined in different examples of light space and in different cases. These examples should be considered as illustrative examples for improving understanding. The concept of the present invention is not limited to these examples, as will be easily understood by those skilled in the art. In FIG. 4A-4D, the light intensity, i.e., illuminance, is assumed to be constant.

[0097] 4A shows an example of a first light space 402. Light space 402 is represented by a two-dimensional cross-section of a graph showing increasing values ​​of circadian stimulation along a first axis 403a and increasing values ​​of color temperature along a second axis 403b.

[0098] As explained above, the light space 402 may be a range of color temperatures and a range of circadian stimuli that the light source can emit. The circadian stimuli and the color temperature may be interdependent. For each value of the circadian stimuli, a set of color temperatures may be possible. Correspondingly, for each value of the color temperature, a set of circadian stimuli may be possible. As is well known in the art, visible light (e.g., white light) may comprise multiple wavelengths of light. The difference between the light of a set of color temperatures for a certain circadian stimulus (or the light of a set of circadian stimuli for a certain color temperature) may be what wavelengths of light it comprises. As an example, light with a certain color temperature may have a first circadian stimulus or a second circadian stimulus. Light with a certain color temperature and a first circadian stimulus may comprise a first set of wavelengths, while light with a certain color temperature and a second circadian stimulus may comprise a second set of wavelengths.

[0099] In the example of Figure 4A, the light space 402 is shown in the shape of a quadrilateral. Note that this is only a non-limiting example. The light space 402 can take other shapes within the circadian stimulus and color temperature domains.

[0100] As a first example, a first target light setting A is shown and marked by a cross. The first target light setting specifies a circadian stimulus of CS-A and a color temperature of CT-A. This example represents the case where the target light setting is within the light space 402, i.e., both the circadian stimulus CS-A and the color temperature CT-A are within the respective ranges of the light space 402. In this case, the target light setting may be set as the light setting of the light source.

[0101] As a second example, a second target light setting B is shown. This represents the case where the target light setting is outside the light space 402. In other words, the light source does not support the second target light setting B, and the light setting of the light source cannot be set to the second target light setting B. Thus, an acceptable light setting is to be determined. In this second example, the circadian stimulation CS-B of the second target light setting B is within the range of the circadian stimulation of the light space 402. In other words, the circadian stimulation CS-B of the second target light setting B is lower than the maximum circadian stimulation CS-max of the light space 402 and higher than the minimum circadian stimulation CS-min of the light space 402. Thus, the circadian stimulation CS-B can be realized. However, the color temperature CT-B of the second target light setting B is outside the range of the color temperature of the light space 402. In this case, the color temperature CT-B of the second target light setting B is higher than the maximum color temperature CT-max of the light space. Alternatively, the color temperature CT-B of the second target light setting B may be outside, in the sense that it is lower than the minimum color temperature CT-min of the light space 402. The acceptable light setting in this case may be determined as the cross indicated by B'. In this example, the circadian stimulus of the acceptable light setting is the same as the target light setting, i.e., CS-B. The color temperature of the acceptable light setting may be selected as any of the color temperatures in the light space 402 that achieves the circadian stimulus CS-B, i.e., any color temperature along the solid line along the level of CS-B. However, as in this case, it may be preferable to select a color temperature that achieves the circadian stimulus CS-B and is as close as possible to the target light setting. Alternatively, the allowed light setting may be selected as the light setting that is closest to the target light setting, but still within the light space. In other words, the acceptable light setting may be selected as the light setting that minimizes the Euclidean distance between the light space and the target light setting.

[0102] As a third example, a third target light setting C is shown. Both the color temperature and the circadian stimulus of the third target light setting C are within their respective ranges of the light space 402. However, the third target light setting C is still outside the light space 402, which means that the combination of the circadian stimulus CS-C and the color temperature CT-C of the third target light setting C is not allowed by the light space 402.

[0103] Referring to the third example, the acceptable light setting may be determined as light setting C', which corresponds to selecting a circadian stimulus that achieves a color temperature CT-C of the third target light setting C. Any light setting on the solid line along the color temperature CT-C may be selected, but preferably, a circadian stimulus that is closest to the circadian stimulus CS-C of the third target light setting C may be selected.

[0104] Referring again to the third example, the acceptable light setting may be determined as light setting C'', which would correspond to selecting a color temperature that achieves the circadian stimulation CS-C of the third target light setting C. Any light setting on the solid line along the circadian stimulation CS-C may be selected, but preferably, a color temperature closest to the color temperature CT-C of the third target light setting C may be selected.

[0105] Referring again to the third example, the acceptable light setting may be determined as light setting C'''. This would correspond to selecting a light setting (i.e., color temperature and circadian stimulus) in light space 402 that minimizes the difference between the selected color temperature and the color temperature CT-C of the third target light setting C, and the difference between the selected circadian stimulus and the circadian stimulus CS-C of the third target light setting C. In other words, light setting C''' would correspond to the light setting in light space 402 that is closest to the third target light setting C.

[0106] FIG. 4B shows, by way of example, how the light space can be determined. A first light space 404 is shown. The first light space 404 may represent the range of circadian stimuli and the range of color temperatures that the light source can emit. A second light space 406 is further shown. The second light space 406 may represent the range of circadian stimuli and the range of color temperatures that the individual's current activity allows. A third light space 408 may be determined as an overlap between the first light space 404 and the second light space 406. Thus, the third light space 408 may represent the range of circadian stimuli and the range of color temperatures that both the light source and the current activity allow. The third light space 408 may then be used as the light space to which the target light setting is compared.

[0107] Referring to the example of FIG. 4B, an example target light setting A would be within the first light space 404, but not within the third light space 408. An acceptable light setting, e.g., A' (the light setting within the third light space 408 that is closest to target light setting A), would then be determined. An example target light setting B would be within the third light space 408, and thus the light setting may be set as target light setting B. An example target light setting C would be outside the third light space 408 (although within the second light space 406). An acceptable light setting, e.g., C' (corresponding to the same circadian stimulus as target light setting C, and the closest color temperature to that of target light setting C), would then be calculated.

[0108] It should be understood that the method for determining acceptable light settings as described with respect to light space 402 of FIG. 4A may be applied to the third light space 408 of FIG. 4B.

[0109] FIG. 4C shows, by way of example, how the light space can be determined. In this case, a fourth light space 410 is shown, which represents the light settings enabled by the light source. In addition, a fifth light space 412 and a sixth light space 414 are shown, which represent the enabled light settings of the respective first and second current activities. A seventh light space 416 is determined as an overlap between the fourth light space 410, the fifth light space 412, and the sixth light space 414, and can be selected as the light space to which the target light setting is compared. In general, any number of current activities can be used to limit the light space.

[0110] It will be appreciated that the method for determining acceptable light settings as described with respect to light space 402 of FIG. 4A and with respect to the third light space 408 of FIG. 4B can be applied to the seventh light space 416 of FIG. 4C.

[0111] FIG. 4D illustrates, by way of example, a case where the range of circadian stimuli and color temperatures of a first current activity and the range of circadian stimuli and color temperatures of a second current activity do not overlap. As in the previous example, an eighth light space 418 is shown. The eighth light space 418 may represent a range of circadian stimuli and a range of color temperatures that a light source can emit. The ninth light space 420 represents a range of circadian stimuli and a range of color temperatures that the first current activity allows. The ninth light space 420 creates a first overlap 424 with the eighth light space 418. The tenth light space 422 represents a range of circadian stimuli and a range of color temperatures that the second current activity allows. The tenth light space 422 creates a second overlap 426 with the eighth light space 418. The first and second current activities may be associated with respective first and second priorities. The light space used to compare the target light setting against may be selected as the first overlap 424 if the first priority is higher than the second priority. Thus, if the target light setting is outside of the first overlap 424, an acceptable light setting within the first overlap 424 may be determined. Alternatively, the light space may be selected as the second overlap 426 if the second priority is higher than the first priority. Thus, if the target light setting is outside of the second overlap 426, an acceptable light setting within the second overlap 426 may be determined.

[0112] It should be understood that the methods for determining allowable light settings as described with respect to light space 402 of Figure 4A and with respect to third light space 408 of Figure 4B may be applied to first overlap 424 and second overlap 426 of Figure 4D. Additionally, variations of the disclosed variations can be understood and implemented by those skilled in the art in practicing the claimed invention, from a study of the drawings, this disclosure, and the appended claims. [Explanation of symbols]

[0113] 100 Systems 102 Light source 104 Individual 106 Electronic Devices 200 Control Device 202 Circuit 204 Processor 206 Transceiver 208 Memory 210 First Decision Function 212 Compare function 214 Setting Function 216 Second Decision Function 218 The third decision function 220 The fourth decision function 222 Control Functions 402 First Light Space, Light Space 403a First axis 403b Second axis 404 The First Light Space 406 The Second Light Space 408 The Third Light Space 410 The Fourth Light Space 412 The Fifth Light Space 414 The 6th Light Space 416 The Seventh Light Space 418 The 8th Light Space 420 The 9th Light Space 422 The 10th Light Space 424 First Duplicate 426 Second Duplicate

Claims

1. 1. A method (300) for determining light settings of a light source configured to illuminate an individual, the light settings of the light source comprising information about a circadian stimulation and a color temperature of light emitted by the light source, the method (300) comprising: determining target light settings for the light source based on a target light profile for the individual, the target light profile comprising time-resolved information about the circadian stimulus and color temperature of the light to which the individual will be exposed, and an actual light profile for the individual, the actual light profile comprising information about the circadian stimulus and color temperature of the light to which the individual has been exposed (S302), the target light settings comprising information about the circadian stimulus and color temperature of the light to be emitted by the light source, and determined such that the actual light profile and the target light profile are aligned over time; comparing the target light setting to a light space (S304), the light space being a range of circadian stimuli and color temperatures of light that the light source can emit; in response to the target light setting being within the light space, Setting the target light setting as the light setting of the light source (S306); in response to the target light setting being outside the light space, determining an acceptable light setting based on the target light setting and the light space (S308), such that the acceptable light setting is within the light space; setting the acceptable light settings as the light settings of the light source (S310); A method (300).

2. The method (300), determining an overlap between the range of circadian stimuli and the range of color temperatures of light that the light source can emit and at least one range of circadian stimuli and at least one range of color temperatures of light enabled by at least one current activity of the individual (S314); Further comprising: The method (300) of claim 1, wherein the light volume is the determined overlap.

3. The method (300), determining (S316) a first overlap between the range of circadian stimuli and the range of color temperatures of light that the light source can emit and the range of circadian stimuli and the range of color temperatures of light enabled by a first current activity of the individual, the first current activity being associated with a first priority; determining (S318) a second overlap between the range of circadian stimuli and the range of color temperatures of light that the light source can emit and the range of circadian stimuli and the range of color temperatures of light enabled by a second current activity of the individual, the second current activity being associated with a second priority; Further comprising:

2. The method of claim 1, wherein the light space is the first overlap if the first priority is higher than the second priority, and is the second overlap if the second priority is higher than the first priority.

4. 4. The method (300) of claim 1, wherein the step (S302) of determining the target light setting is further based on a range of circadian stimulation and a range of color temperatures of light allowed by the individual's future activities.

5. The step of determining the acceptable light settings (S308) further comprises: if the circadian stimulus of the target light setting is within the range of the circadian stimulus of the light space and the color temperature of the target light setting is outside the range of the color temperature of the light space; selecting a color temperature within the range of color temperatures of the light space that achieves the circadian stimulus of the target light setting (S320); and Setting the circadian stimulus and the selected color temperature of the target light setting as the acceptable light setting (S322); if the circadian stimulus of the target light setting is outside the range of the circadian stimulus of the light space and the color temperature of the target light setting is within the range of the color temperature of the light space; selecting a circadian stimulus within the range of the circadian stimuli of the light space that achieves the color temperature of the target light setting (S324); and setting the selected circadian stimulus and the color temperature of the target light setting as the acceptable light setting (S326); or if the circadian stimulus of the target light setting is within the range of the circadian stimulus of the light space and the color temperature of the target light setting is within the range of the color temperature of the light space; selecting a color temperature within the range of color temperatures of the light space that achieves the circadian stimulus of the target light setting (S328); and setting the circadian stimulus and the selected color temperature of the target light setting as the acceptable light setting (S330); or selecting a circadian stimulus within the range of the circadian stimuli of the light space that achieves the color temperature of the target light setting (S332); and Setting the selected circadian stimulus and the color temperature of the target light setting as the acceptable light setting (S334).

5. The method (300) of any one of claims 1 to 4, comprising:

6. The step of determining the acceptable light settings (S308) further comprises: Selecting a color temperature and a circadian stimulus within the light space that minimizes the difference between a selected color temperature and the color temperature of the target light setting, and between a selected circadian stimulus and the circadian stimulus of the target light setting (S336); setting the selected color temperature and the selected circadian stimulus as the acceptable light settings (S338); 5. The method (300) of any one of claims 1 to 4, comprising:

7. 7. The method (300) of any one of claims 1 to 6, further comprising a step (S312) of controlling the light source in accordance with the light settings such that the actual light profile of the individual is aligned with the target light profile of the individual over time.

8. A control device (200) for determining light settings of a light source configured to illuminate an individual, the light settings of the light source comprising information about a circadian stimulation and a color temperature of light emitted by the light source, the control device (200) comprising: A circuit (202), the circuit (202) comprising: a first determining function (210) configured to determine a target light setting of the light source based on a target light profile of the individual comprising time-resolved information on the circadian stimulus and color temperature of light to which the individual will be exposed and an actual light profile of the individual comprising information on the circadian stimulus and color temperature of light to which the individual has been exposed, the target light setting comprising information on the circadian stimulus and color temperature of light to be emitted by the light source and determined such that the actual light profile and the target light profile are aligned over time; a comparison function (212) configured to compare the target light setting with a light space, the light space being a range of circadian stimuli and a range of color temperatures of light that the light source can emit; a setting function (214) configured to set the target light setting as the light setting of the light source in response to the target light setting being within the light space; a second determination function (216) configured to, in response to the target light setting being outside the light space, determine an acceptable light setting based on the target light setting and the light space, such that the acceptable light setting is within the light space; configured to run A control device (200), wherein the setting function (214) is further configured to set the acceptable light setting as the light setting of the light source in response to the target light setting being outside the light space.

9. the circuit (200) is further configured to perform a third determining function (218) configured to determine an overlap between the range of circadian stimuli and the range of color temperatures of light that the light source can emit and at least one range of circadian stimuli and at least one range of color temperatures of light enabled by at least one current activity of the individual; The control device (200) of claim 8, wherein the light space is the determined overlap.

10. The circuit (202) is further configured to perform a fourth decision function (220), the fourth decision function (220) being: determining a first overlap between the range of circadian stimuli and the range of color temperatures of light that the light source can emit and a range of circadian stimuli and a range of color temperatures of light enabled by a first current activity of the individual, the first current activity being associated with a first priority; the fourth determining function (220) is configured to determine a second overlap between the range of circadian stimuli and the range of color temperatures of light that the light source can emit and a range of circadian stimuli and a range of color temperatures of light enabled by a second current activity of the individual, the second current activity being associated with a second priority; 10. The control device (200) of claim 8, wherein the light space is the first overlap when the first priority is higher than the second priority, and is the second overlap when the second priority is higher than the first priority.

11. 11. The control device (200) of any one of claims 8 to 10, wherein the first determination function (210) is further configured to determine the target light setting further based on a range of circadian stimulation and a range of color temperatures of light allowed by the individual's future activities.

12. The second decision function (216): if the circadian stimulus of the target light setting is within the range of the circadian stimulus of the light space and the color temperature of the target light setting is outside the range of the color temperature of the light space; selecting a color temperature within the color temperature range of the light space that achieves the circadian stimulation of the target light setting; and setting the circadian stimulus and the selected color temperature of the target light setting as the acceptable light setting; if the circadian stimulus of the target light setting is outside the range of the circadian stimulus of the light space and the color temperature of the target light setting is within the range of the color temperature of the light space; selecting a circadian stimulus within the range of the circadian stimuli of the light space that achieves the color temperature of the target light setting; and setting the selected circadian stimulus and the color temperature of the target light setting as the acceptable light setting; or if the circadian stimulus of the target light setting is within the range of the circadian stimulus of the light space and the color temperature of the target light setting is within the range of the color temperature of the light space; selecting a color temperature within the color temperature range of the light space that achieves the circadian stimulation of the target light setting; and setting the circadian stimulus and the selected color temperature of the target light setting as the acceptable light setting; or selecting a circadian stimulus within the range of the circadian stimuli of the light space that achieves the color temperature of the target light setting; and setting the selected circadian stimulus and the color temperature of the target light setting as the acceptable light setting. A control device (200) according to any one of claims 8 to 11, configured to:

13. The second decision function (216): selecting a color temperature and a circadian stimulus within the light space that minimizes a difference between a selected color temperature and the color temperature of the target light setting, and a difference between a selected circadian stimulus and the circadian stimulus of the target light setting; setting the selected color temperature and the selected circadian stimulus as the acceptable light settings; A control device (200) according to any one of claims 8 to 12, configured to:

14. The control device (200) according to any one of claims 8 to 13, wherein the light source is an electronic display.

15. A non-transitory computer readable storage medium having program code portions recorded thereon which, when executed on a device having processing capabilities, performs the method (300) of any one of claims 1 to 7.

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