Patent Publication Number: US-11665797-B2

Title: Indoor lighting control based on outdoor light

Description:
The present application is a continuation application of and claims priority to U.S. Nonprovisional patent application Ser. No. 15/908,537, filed Feb. 28, 2018 and titled “Indoor Lighting Control Based on Outdoor Light.” The entire contents of the preceding application are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates generally to lighting solutions, and more particularly to controlling indoor lighting based on outdoor light. 
     BACKGROUND 
     During daytime, indoor spaces are often illuminated independently of lighting conditions on the outside of the indoor spaces. For example, the light provided by an indoor lighting fixture is often the same regardless of the time of day. As another example, the light provided by an indoor lighting fixture is often the same regardless of the weather condition outdoors. Even when the intensity of the indoor light is adjusted, the correlated color temperature (CCT) may be left unchanged or may be changed independently of outdoor lighting conditions. However, the quality of the indoor light is generally at its highest if the CCT and the color quality (color rendering index (CRI)) of the indoor light matches or correlates with the CCT and CRI of the outdoor daylight. Further, CCT and light quality matching between indoor lighting and outdoor lighting may be beneficial in maintaining the Circadian Rhythm. For example, a warmer CCT is generally preferred as the outdoor light level is lower during morning and evening hours, and a cooler CCT may be generally preferred during daytime between the morning and evening hours. Thus, a solution that provides improved and adaptive indoor lighting may be desirable. 
     SUMMARY 
     The present disclosure relates generally to lighting solutions, and more particularly to controlling indoor lighting based on outdoor light. In an example embodiment, a lighting fixture includes a light source that emits an illumination light and a receiver configured to receive a lighting control message from a photo sensor device. The lighting fixture further includes a lighting controller configured to adjust the illumination light based on the lighting control message. Adjusting the illumination light by the lighting controller includes changing a Correlated Color Temperature (CCT) of the illumination light. 
     In another example embodiment, a photo sensor device includes a light sensor circuit configured to sense multiple components of an outdoor light that are in multiple ranges of wavelengths. The light sensor circuit is further configured to generate a lighting control message based on the multiple components of the outdoor light. The photo sensor device further includes a transmitter configured to transmit the lighting control message. 
     In another example embodiment, a lighting system includes a lighting fixture that emits an illumination light to illuminate an indoor space and a photo sensor device located to sense an outdoor light. The photo sensor device is configured to generate a lighting control message based on the outdoor light. The lighting fixture is configured to adjust a Correlated Color Temperature (CCT) of the illumination light based on the lighting control message. 
     These and other aspects, objects, features, and embodiments will be apparent from the following description and the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       Reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein: 
         FIG.  1    illustrates a lighting system that adjusts an indoor light based on an outdoor light according to an example embodiment; 
         FIG.  2    illustrates a CCT value curve of an outdoor light with respect to different times of day according to an example embodiment; 
         FIG.  3    illustrates details of the lighting system of  FIG.  1    according to an example embodiment; 
         FIG.  4    illustrates different components of the outdoor light with respect to different ranges of wavelengths according to an example embodiment; and 
         FIG.  5    illustrates details of the lighting system of  FIG.  1    according to another example embodiment. 
     
    
    
     The drawings illustrate only example embodiments and are therefore not to be considered limiting in scope. The elements and features shown in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the example embodiments. Additionally, certain dimensions or placements may be exaggerated to help visually convey such principles. In the drawings, the same reference numerals that are used in different drawings designate like or corresponding, but not necessarily identical elements. 
     DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS 
     In the following paragraphs, example embodiments will be described in further detail with reference to the figures. In the description, well known components, methods, and/or processing techniques are omitted or briefly described. Furthermore, reference to various feature(s) of the embodiments is not to suggest that all embodiments must include the referenced feature(s). 
     Turning now to the figures, particular example embodiments are described.  FIG.  1    illustrates a lighting system  100  that adjusts an indoor light based on an outdoor light according to an example embodiment. In some example embodiments, the system  100  includes a lighting fixture  104  and a photo sensor device  106 . The lighting fixture  104  may provide an illumination light  116  to an indoor space  112  inside a building  102  (e.g., a residential or office building) or a similar structure. For example, the indoor space  112  may be a room, a hallway, underground facility, etc. inside the building  102 . The lighting fixture  104  may be a suspended lighting fixture, a recessed lighting fixture, or another type of lighting fixture. For example, the lighting fixture  104  may be suspended from or recessed in a ceiling of the building  102 . 
     In some example embodiments, the building  102  may have one or more windows  110  through which outdoor light  114  from outside of the building enters the indoor space  112 . The outdoor light  114  may be reflected off objects, such as trees, other buildings, terrain, etc. and surfaces that may contribute to the characteristics of the outdoor light  114 . The indoor space  112  may be illuminated by the outdoor light  114  entering through the one or more windows and the illumination light  116  provided by the lighting fixture  104 . In some alternative embodiments, the indoor space  112  may be fully or mostly devoid of outdoor light  114 . For example, the indoor space  112  may be a room or a space that is too deep inside the building  102  to receive a meaningful amount of the outdoor light  114 . As another example, the building  102  may not have the one or more windows  110 . 
     In some example embodiments, the photo sensor device  106  may be located at least partially outside of the building  102  to sense the outdoor light  114 . For example, the photo sensor device  106  may be attached to the building  102  or another structure that is outside of the building  102 . Alternatively, the photo sensor device  106  may be located on the inside of the building  102  in a manner that allows the photo sensor device  106  to sense the outdoor light  114 . 
     In some example embodiments, the photo sensor device  106  may sense the outdoor light  114  and generate one or more lighting control messages based on the outdoor light  114 . The photo sensor device  106  may transmit the lighting control message to the lighting fixture  104  using one or more signals  118 . For example, the photo sensor device  106  may wirelessly transmit one or more signals  118  that carry the lighting control message to the lighting fixture  104  wirelessly. Alternatively, the photo sensor device  106  may transmit the lighting control message to the lighting fixture  104  via a wired connection. 
     In some example embodiments, the lighting fixture  104  may receive the lighting control message and adjust the illumination light  116  based on the lighting control message. To illustrate, the lighting fixture  104  may set or adjust the CCT of the illumination light  116  based on the lighting control message. For example, the lighting fixture  104  may change the CCT of the illumination light to closely/substantially match a CCT of the outdoor light  114  sensed by the photo sensor device  106 . 
     In some example embodiments, the lighting fixture  104  may set or adjust the CCT of the illumination light  116  based on one or more of the different types of information included in the lighting control message received from the photo sensor device  106 . To illustrate, the lighting fixture  104  may set or adjust the CCT of the illumination light  116  based on the information in the lighting control message that indicates or corresponds to the light level of the outdoor light  114 . For example, the lighting control message may include a value that indicates a light level of the outdoor light  114 . A lower value may indicate a light level that is typically present during early morning or evening times, a higher value may indicate a light level that is typically present during daytime between early morning and evening times, and a value that is below a particular threshold may indicate nighttime. 
     In some example embodiments, the lighting fixture  104  may set or adjust the CCT of the illumination light  116  based on the information in the lighting control message that indicates or corresponds to the blue light component of the outdoor light  114 . To illustrate, the blue light component of the outdoor light  114  may correspond to a wavelength range (e.g., ˜425 nm to ˜500 nm) of the outdoor light  114 . For example, the lighting control message may include a value that indicates or corresponds to the amplitude of the blue light component of the outdoor light  114 . 
     In some example embodiments, the lighting fixture  104  may set or adjust the CCT of the illumination light  116  based on information that indicates or corresponds to other components of the outdoor light  114  instead of or in addition to the light level and/or the blue light component of the outdoor light  114 . For example, the lighting control message may include information that indicates or corresponds to other types of information such as red light component and/or other components of the outdoor light  114 . To illustrate, the lighting control message may include information that indicates or corresponds to the light level of the outdoor light  114 , to the blue light component of the outdoor light  114 , and/or to other information such red light component and/or green light component of the outdoor light  114 . 
     In some example embodiments, the lighting control message may include information that indicates or corresponds to one or more components of the outdoor light  114  with respect to one or more wavelength ranges as determined by the photo sensor device  106 . Components of the outdoor light  114  with respect to different wavelength ranges are shown in  FIG.  5    according to an example embodiment. 
     In some example embodiments, the lighting control message may include information that indicates a CCT value that the illumination light  116  should have. To illustrate, the lighting control message may include a value (e.g., a voltage value) that can be used by the lighting fixture  104  to set the CCT of the illumination light to a particular CCT value corresponding to the value included in the lighting control message. 
     In some example embodiments, the lighting fixture  104  may operate in a particular mode based on the lighting control message. For example, the lighting fixture  104  may operate in a daylight mode, in a low light mode, or in another mode depending on the information contained in the lighting control message. To illustrate, the lighting fixture  104  may operate in a particular mode based on one or more of a light level of the outdoor light  114 , blue light component of the outdoor light  114 , and/or other information that may be contained in the lighting control message indicating the outdoor lighting condition. For example, the lighting fixture  104  may operate in a daylight mode when the lighting control message indicates that the outdoor lighting condition corresponds to a daylight lighting condition that is typically present between early morning (e.g., between sunrise and 8 a.m.) and evening (e.g., between 5 p.m. and sunset) times. It is to be understood that typical early morning and evening times may vary based on location and/or season. 
     In the daylight mode, the lighting fixture  104  may operate such that the CCT of the illumination light  116  ranges between a first CCT value (e.g., −4500K) and a second CCT value (e.g., −6500K). For example, in the daylight mode, the lighting fixture  104  may adjust the CCT of the illumination light  116  between the first and second CCT values regardless of the dim level setting of the lighting fixture  104 . 
     In some example embodiments, the lighting fixture  104  may operate in a low light mode when the lighting control message indicates that the outdoor lighting condition corresponds to a low lighting condition that is typically present during early morning (e.g., between sunrise and 8 a.m.) and evening (e.g., between 5 p.m. and sunset) times. For example, the lighting fixture  104  may operate in the low light mode if the lighting control message received from the photo sensor device  106  indicates a low light level, low blue light component, and/or relatively high red light component of the outdoor light  114 . 
     In some example embodiments, in the low light mode, the lighting fixture  104  may set or adjust the CCT of the illumination light  116  based on the dim level setting of the lighting fixture  104 . To illustrate, during the low light mode, the lighting fixture  104  may adjust the CCT of the illumination light  116  may set to a particular CCT value when the dim level of the illumination light  116  is set to threshold dim level. Alternatively or in addition, the lighting fixture  104  may adjust the CCT of the illumination light  116  in correlation with adjustments of the dim level setting of the lighting fixture  104 . For example, the lighting fixture  104  may adjust the CCT of the illumination light  116  to different CCT values (e.g., 3000K, 2000K, 1000K, etc.) when the dim level of the illumination light  116  is adjusted to corresponding dim levels (e.g., 70%, 50%, 30%, etc.). 
     By adjusting the CCT of the illumination light  116  based on the outdoor lighting condition indicated by the lighting control message from the photo sensor device  106 , the illumination light  116  may provide improved lighting inside the building  102 . For example, the illumination light  116  may have improved quality by adjusting the CCT of the illumination light  116  to have a CCT that closely/substantially matches the CCT of the outdoor light  114 . For example, the illumination light  116  may be adjusted based on the lighting control message to have a CCT that is within 100K of the CCT of the outdoor light  114 . To illustrate, between early morning and evening times, the CCT of the illumination light  116  may be adjusted by the lighting fixture  104  to in a range of approximately 6400K to 6600K when the CCT of the outdoor light is approximately 6500K. As another example, the CCT of the illumination light  116  may be adjusted by the lighting fixture  104  to be in a range of approximately 4400K to 4600K when the CCT of the outdoor light is approximately 4500K. Further, during early morning and evening times, adjusting the CCT of the illumination light  116  in correlation with the dim level setting provides improved indoor lighting quality. 
     In some example embodiments, the photo sensor device  106  can also send other types of information that can be used to automate the building  102  in response to outdoor elements, such as sunshine, temperature, seasonal changes, humidity and/or moisture. For example, the temperature, humidity, etc. of the indoor space  112  may be adjusted based on corresponding information provided by the photo sensor device  106 . 
     In some alternative embodiments, the system  100  may include multiple lighting fixtures that receive one or more lighting control messages from the photo sensor device  106 . For example, different lighting fixtures that receive the one or more lighting control messages from the photo sensor device  106  may be in different parts of the building  102 , such as in different rooms of the building  102 . In some alternative embodiments, the lighting fixture  104  and the photo sensor device  106  may be at different locations than shown in  FIG.  1    without departing from the scope of this disclosure. 
       FIG.  2    illustrates a CCT value curve  200  of the outdoor light  114  with respect to different times of day according to an example embodiment. Referring to  FIGS.  1  and  2   , in some cases, the CCT of the outdoor light  114  may be approximately 2000K at sunrise and may increase to approximately 4000K at the end of early morning (e.g., 8 a.m.). From the end of early morning, the CCT of the outdoor light  114  may increase up to approximately 6500K and decrease back to approximately 4000K by late afternoon (e.g., 5 p.m.). The CCT of the outdoor light  114  may continue to decrease down to approximately 2000K at sunset. It is to be understood that typical early morning and evening times may vary based on location, season, etc. It is also to be understood that the CCT of the outdoor light may depend on weather conditions and other factors such as air quality, etc. 
       FIG.  3    illustrates details of the lighting system  100  of  FIG.  1    according to an example embodiment. Referring to  FIGS.  1 - 3   , in some example embodiments, the photo sensor device  106  includes a light sensor circuit  302 , a transmitter  304 , a battery  316 , and a photovoltaic cell/unit  318 . The light sensor circuit  302  may sense the outdoor light  114  and generate the lighting control message described above. For example, the light sensor circuit  302  may sense one or more of the light levels of the outdoor light  114 , the blue light component of the outdoor light  114 , the components of the outdoor light  114  in different wavelength ranges, etc. and generate the lighting control message based on the sensed information. The light sensor circuit  302  provides the lighting control message to the transmitter  304  that transmits the lighting control message wirelessly or via a wired connection. 
     In some example embodiments, the light sensor circuit  302  senses one or more components of the outdoor light  114  that are in one or more ranges of wavelengths. To illustrate, a first component of the outdoor light  114  may be in a first range of wavelengths (e.g., ˜425 nm to ˜500 nm), and a second component of the outdoor light  114  may be in a second range of wavelengths (e.g., 600 nm to 650 nm). For example, different components of the outdoor light  114  with respect to different ranges of wavelengths are shown in  FIG.  4    for a particular time of the day according to an example embodiment. Some of the ranges of wavelengths may be non-overlapping with each other, while other ranges of wavelengths may overlap. In  FIG.  4   , the lower range component may correspond to the blue light component of the outdoor light  114 , the upper range component may correspond to the red light component of the outdoor light  114 , and the middle range component may correspond to the green light component of the outdoor light  114 . The light sensor circuit  302  may determine the amplitude of one or more of the different components corresponding to the one or more ranges of wavelengths and generate the lighting control message accordingly. 
     Referring to  FIGS.  1 - 4   , in some example embodiments, the battery  316  may provide electrical power to the transmitter  304  and to the light sensor circuit  302 . For example, the photovoltaic cell  318  may convert solar energy into electrical power that is used to charge battery  316 , which in turn can power the transmitter  304  and the light sensor circuit  302 . 
     In some example embodiments, the lighting fixture  104  includes a receiver  306 , a lighting controller  308 , a driver  310 , and a light source  312  such as a light emitting diode (LED) light source. For example, the driver  310  may be an LED driver. The light source  312  may include white LEDs and other phosphor converted color LEDs that together can produce the illumination light  116  that may be a full spectrum high quality light. For example, the illumination light  116  may be adjusted to closely match daylight. 
     In some example embodiments, the lighting controller  308  may control the illumination light  116  based on the dim level setting and the lighting control message from the photo sensor device  106 . To illustrate, the lighting controller  308  may set/adjust the light level of the illumination light  116  based on the received dim level setting or command. For example, the receiver  306  or another component of the lighting fixture  104  may receive the dim level setting or command from a wall-mounted control device  314  (e.g., a wall dimmer, a wall station, etc.) or from another control device wirelessly or via a wired connection. 
     In some example embodiments, the lighting controller  308  may set/adjust the CCT of the illumination light  116  based on the lighting control message. For example, the receiver  306  may receive the lighting control message from the photo sensor device  106  and provide the lighting control message to the lighting controller  308 . The lighting controller  308  may set/adjust the CCT of the illumination light  116  based on the information contained in the lighting control message in a manner described above. To illustrate, the lighting controller  308  may process the lighting control message to determine the information contained therein and control the CCT of the illumination light  116  accordingly. 
     For example, the lighting control message may indicate the CCT of the outdoor light  114 , and the lighting controller  308  may process the lighting control message and change the CCT of the illumination light  116  to closely match the CCT of the outdoor light  114 . As another example, the lighting control message may indicate the blue and/or other light components of the outdoor light  114 , and the lighting controller  308  may process the lighting control message and adjust the illumination light  116  to have similar blue and/or other components that can result in the CCT of the illumination light  116  closely matching the CCT of the outdoor light  114 . As another example, the lighting control message may indicate the component of the outdoor light  114  in one or more wavelength ranges, and the lighting controller  308  may process the lighting control message and adjust the illumination light  116  to have a similar component that can result in the CCT of the illumination light  116  closely matching the CCT of the outdoor light  114 . 
     In some example embodiments, the lighting control message may indicate the light level of the outdoor light  114 , and lighting controller  308  may operate the lighting fixture  104  in a daylight mode, in a low light mode, or in another mode depending on the light level indicated by the lighting control message. Alternatively or in addition, the controller  308  may use other information, such as the blue light component of the outdoor light  114  indicated by the lighting control message, to determine whether to operate the lighting fixture  104  in a particular mode. In some example embodiments, the lighting controller  308  may include hardware (e.g., a CPU, a memory device, etc.), a software code, or a combination of thereof to perform its operations. 
     In some alternative embodiments, the receiver  306  and the lighting controller  308  may be integrated into a single component or into the driver  310  without departing from the scope of this disclosure. In some example embodiments, the wall-mounted control device  314  may be omitted without departing from the scope of this disclosure. In some alternative embodiments, one or more components (e.g., the solar cell  318 ) of the photo sensor device  106  may be omitted or integrated into a single component. 
       FIG.  5    illustrates details of the lighting system  100  of  FIG.  1    according to another example embodiment. Referring to  FIGS.  1 - 5   , in some example embodiments, the light sensor circuit  302  may include light sensor elements  502 ,  504 ,  506  that can sense different components of the outdoor light  114 . For example, the light sensor element  502  may sense the component of the outdoor light  114  in the lower range shown in  FIG.  4   , the light sensor element  504  may sense the component of the outdoor light  114  in the middle range, and the light sensor element  506  may sense the component of the outdoor light  114  in the upper range. That is, each light sensor element  502 ,  504 ,  506  may have a photosensitivity that corresponds to a particular range of wavelengths of the outdoor light  114 . The light sensor elements  502 ,  504 ,  506  may each output one or more electrical signals based on the sensing of the respective component of the outdoor light  114 . 
     In some example embodiments, the light sensor circuit  302  may also include a sensor controller  508  that can process electrical signals from the light sensor elements  502 ,  504 ,  506  and generate the lighting control message described above. For example, the sensor controller  508  may generate the lighting control message that includes information (e.g., one or more values) indicating one or more of the CCT of the outdoor light  114 , a light level of the outdoor light  114 , a particular component (e.g., blue component amount) of the outdoor light  114 , etc. The sensor controller  508  may include hardware (e.g., a CPU, a memory device, etc.), a software code, or a combination thereof to perform its operations. 
     In some example embodiments, the transmitter  304  may receive the lighting control message from the sensor controller  508  and transmit the lighting control message wirelessly or via a wired connection. The transmitter  304  may transmit the lighting control message in compliance with a communication standard such as Wi-Fi and Ethernet standards. 
     In some example embodiments, the lighting fixture  104  may include and may be in communication with a lighting control circuit  510  that receives the lighting control message transmitted by the transmitter  304 . For example, the lighting control circuit  510  may include the receiver  306 , the lighting controller  308 , and the driver  310  more clearly shown in  FIG.  3    and may perform the operations described above with respect to the components. The lighting control circuit  510  may receive and process the lighting control message and adjust the CCT of the illumination light  116  based on the information contained in the lighting control message as described above. As described above, the CCT of the illumination light  116  may be adjusted based on the lighting control message to closely match the CCT of the outdoor light  114 . For example, the lighting control circuit  510  may control the amount of power provided to the different LED branches of the light source  312 , where, for example, different LED branches emit lights dominated by a respective CCT such that the combination of the lights has a desired CCT. The CCT of the illumination light  116  may be adjusted periodically or continuously to maintain the CCT of the illumination light  116  in close match with the CCT of the outdoor light  114 . 
     In some example embodiments, the CCT of the illumination light  116  may be limited within a range of CCT values (e.g., 4500K-6500K) during the daylight mode described above. In some example embodiments, the CCT of the illumination light  116  may also be limited to below a particular CCT (e.g., 3000K) during the low light mode described above. 
     By providing indoor lighting that has a CCT that closely matches the CCT of the outdoor light, improved color perception may be achieved in indoor environments. The close matching of the CCT of the illumination light  116  to the CCT of the outdoor light  114  may also help maintain the Circadian Rhythm of occupants of the indoor space  112 . During low outdoor light conditions, such early morning and evening hours, the adjustment of the CCT of the illumination light  116  based on the dim level setting enables the gradual introduction and removal of the blue light by gradually increasing and decreasing the CCT of the illumination light  116  in correlation with the adjustment of the dim level. 
     In some alternative embodiments, the light sensor circuit  302  may include more or fewer light sensor elements than shown in  FIG.  5    without departing from the scope of this disclosure. In some alternative embodiments, one or more components of the light sensor circuit  302  and/or the transmitter  304  may be combined without departing from the scope of this disclosure. In some alternative embodiments, the light source  312  may include more or fewer LED branches than shown without departing from the scope of this disclosure. 
     Although particular embodiments have been described herein in detail, the descriptions are by way of example. The features of the example embodiments described herein are representative and, in alternative embodiments, certain features, elements, and/or steps may be added or omitted. Additionally, modifications to aspects of the example embodiments described herein may be made by those skilled in the art without departing from the spirit and scope of the following claims, the scope of which are to be accorded the broadest interpretation so as to encompass modifications and equivalent structures.