Patent Publication Number: US-11029008-B2

Title: Lighting fixture including a color changing component

Description:
FIELD OF THE DISCLOSURE 
     The present disclosure is related to lighting fixtures, and in particular to lighting fixtures including a color changing component that may be used to improve the aesthetics of the lighting fixtures, simulate an outdoor environment, and/or convey information from the lighting fixtures. 
     BACKGROUND 
     Modern lighting devices such as lighting fixtures may include intelligent features such as network connectivity, programming capability, detection of environmental conditions via a number of sensors, and the like. However, there has thus far been a limitation in lighting fixtures in their ability to convey information to a person in the vicinity thereof. While previous approaches have focused on changing a characteristic (e.g., color) of light provided from a lighting fixture to convey information, these approaches have been significantly disruptive in terms of the effect they have on individuals near the lighting fixture. For example, if a lighting fixture were to change the color of the light provided therefrom from typical white to red to convey some kind of information, such a drastic change in the color of the light may be highly disruptive to individuals near the lighting fixture and may thus cause interruptions in the activities of these individuals. Similarly, flashing the light from a lighting fixture to convey information is also disruptive in many circumstances. Accordingly, there is a need for lighting fixtures and methods for operating the lighting fixtures in order to convey information without disruption to individuals surrounding the lighting fixtures. 
     In addition to the above, there has been recent work on lighting fixtures that simulate outdoor environments. Simulating outdoor environments using lighting fixtures may provide certain health benefits and improvements in the mood of individuals in an indoor space. However, current lighting fixtures have difficulty simulating a full range of outdoor conditions such as overhead clouds and night skies. Accordingly, there is a need for lighting fixtures and methods for operating the lighting fixtures in order to more accurately simulate outdoor environments. 
     SUMMARY 
     In one embodiment, a lighting fixture includes a housing, a light source, and a diffuser. The light source is mounted in the housing. The diffuser is also mounted in the housing such that light emitted from the light source is provided through the diffuser towards an area of interest. The diffuser is configured such that a color of the diffuser is based on one or more characteristics of the light emitted from the light source. Providing the diffuser such that the color thereof is based on one or more characteristics of the light emitted from the light source allows the aesthetic appearance of the lighting fixture to be changed. Further, it allows the lighting fixture to better simulate outdoor environments. Finally, it allows the lighting fixture to convey information to individuals near the lighting fixture without being disruptive. 
     In one embodiment, the lighting fixture includes an additional light source and control circuitry. The control circuitry is coupled to the light source and the additional light source and configured to individually adjust one or more characteristics of the light provided by the light source and the additional light source. In one embodiment, the control circuitry is configured to adjust one or more characteristics of the light provided by the light source in order to change a color of the diffuser and adjust one or more characteristics of the light provided by the additional light source such that one or more characteristics of a combination of the light provided by the light source and the light provided from the additional light source remain constant. Accordingly, the color of the diffuser can be changed to change an aesthetic appearance of the lighting fixture, simulate an outdoor environment, or convey information while simultaneously providing light suitable for general illumination. 
     In one embodiment, a method includes the steps of providing light from a light source through a diffuser towards an area of interest and changing one or more characteristics of the light provided from the light source in order to change a color of the diffuser. The method may further include providing light from an additional light source towards the area of interest and changing one or more characteristics of the light provided by the additional light source to offset the change in the one or more characteristics of the light source such that one or more characteristics of a combination of the light provided by the light source and the light provided by the additional light source remains constant. This method allows for the adjustment of the color of the diffuser to change an aesthetic appearance of a lighting fixture, simulate an outdoor environment, or convey information while simultaneously providing light suitable for general illumination. 
     Those skilled in the art will appreciate the scope of the present disclosure and realize additional aspects thereof after reading the following detailed description of the preferred embodiments in association with the accompanying drawing figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
       The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the disclosure, and together with the description serve to explain the principles of the disclosure. 
         FIG. 1  illustrates a lighting fixture according to one embodiment of the present disclosure. 
         FIG. 2  illustrates a lighting fixture according to one embodiment of the present disclosure. 
         FIG. 3  illustrates a lighting fixture according to one embodiment of the present disclosure. 
         FIG. 4  illustrates a light source and a diffuser for a lighting fixture according to one embodiment of the present disclosure. 
         FIG. 5  illustrates a lighting fixture according to one embodiment of the present disclosure. 
         FIGS. 6A and 6B  illustrate a diffuser for a lighting fixture according to one embodiment of the present disclosure. 
         FIG. 7  illustrates a lighting fixture according to one embodiment of the present disclosure. 
         FIG. 8  is a flow diagram illustrating a method for operating a lighting fixture according to one embodiment of the present disclosure. 
         FIG. 9  illustrates control circuitry for a lighting fixture according to one embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The embodiments set forth below represent the necessary information to enable those skilled in the art to practice the embodiments and illustrate the best mode of practicing the embodiments. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the disclosure and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure and the accompanying claims. 
     It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the present disclosure. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     It will be understood that when an element such as a layer, region, or substrate is referred to as being “on” or extending “onto” another element, it can be directly on or extend directly onto the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly on” or extending “directly onto” another element, there are no intervening elements present. Likewise, it will be understood that when an element such as a layer, region, or substrate is referred to as being “over” or extending “over” another element, it can be directly over or extend directly over the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly over” or extending “directly over” another element, there are no intervening elements present. It will also be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present. 
     Relative terms such as “below” or “above” or “upper” or “lower” or “horizontal” or “vertical” may be used herein to describe a relationship of one element, layer, or region to another element, layer, or region as illustrated in the Figures. It will be understood that these terms and those discussed above are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes,” and/or “including” when used herein specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
       FIG. 1  shows a lighting fixture  10  according to one embodiment of the present disclosure. The lighting fixture  10  includes a housing  12 , a light source  14  in the housing  12 , a diffuser  16  in the housing  12 , a power source  18 , and control circuitry  20  coupled between the power source  18  and the light source  14 . In some embodiments, the lighting fixture  10  may further include a number of sensors  22 , which are coupled to the control circuitry  20  and provide sensor data thereto. In operation, the control circuitry  20  receives power from the power source  18  and provides one or more drive signals to control light emitted from the light source  14 . In particular, the control circuitry  20  may provide drive signals such that one or more characteristics of light emitted from the light source  14  are precisely controlled. For example, the control circuitry  20  may be capable of changing a brightness, color temperature, color rendering index, color, or any other characteristic of the light provided from the light source  14 . The control circuitry  20  may be further capable of communicating with remote devices such as other lighting fixtures or controls in order to change one or more characteristics of the light provided from the light source  14  in response to automation programs, user input, or the like. Light emitted from the light source  14  is provided towards an area of interest through the diffuser  16  such that some of the light emitted from the light source  14  is provided directly towards the area of interest and the remainder of the light emitted from the light source  14  is provided indirectly towards the area of interest as it is reflected one or more times within a mixing area within the housing  12  bounded by the diffuser  16 . 
     Notably, the diffuser  16  comprises a color changing material such that when the diffuser  16  is primarily front-lit from a light source outside of the housing  12 , the diffuser  16  appears to be a first color and when the diffuser is primarily back-lit from the light source  14  in the housing  12 , the diffuser  16  appears to be a second color that is different from the first color. For example, the diffuser  16  may appear to be black or dark grey when it is primarily front-lit and appear to be white or light grey when it is primarily back-lit. The color of the diffuser  16  may not be binary, such that the color of the diffuser  16  may vary between the first color and the second color depending on the amount of front-lighting and back-lighting of the diffuser  16 . Examples of the color changing material of the diffuser include Acrylite 9K004 GT, the datasheet of which is hereby incorporated by reference in its entirety, and Acrylite 9H04 SC, the datasheet of which is hereby incorporated by reference in its entirety. Those skilled in the art will appreciate that any number of materials may be used to provide the color changing effect of the diffuser  16 , all of which are contemplated herein. 
     Using a color changing material for the diffuser  16  may provide several benefits. First, the aesthetic appearance of the lighting fixture  10  may be improved. Second, the diffuser  16  may allow the lighting fixture  10  to better simulate outdoor environments that were previously difficult to simulate using a lighting fixture  10 , for example, overhead clouds and night skies. This may be especially useful, for example, in lighting fixtures that are configured to provide a simulated skylight experience such as the lighting fixtures described in co-assigned and co-pending U.S. patent application Ser. No. 15/972,176, now U.S. Pat. No. 10,465,869, the contents of which are hereby incorporated by reference in their entirety. Finally, the diffuser  16  may allow the lighting fixture  10  to convey information to individuals around the lighting fixture  10  without disrupting the individuals. That is, the diffuser  16  may allow the lighting fixture  10  to convey information to individuals around the lighting fixture  10  while continuing to provide light suitable for general illumination. 
     The light source  14  may be a solid-state light source including one or more light emitting diodes (LEDs). The one or more LEDs may be arranged in an array or in groups such that different ones of the LEDs provide different light output characteristics. The control circuitry  20  may control one or more characteristics of the light emitted from each one of the LEDs in order to provide a combined light output with desired characteristics. While shown having a particular shape for purposes of illustration, the housing  12  may comprise any suitable shape. For example, the housing  12  may be used to provide a troffer lighting fixture, a recessed lighting fixture, or any other desired lighting fixture. 
     While the diffuser  16  is shown as a continuous sheet in the lighting fixture  10  depicted in  FIG. 1 , the diffuser  16  may be broken up into one or more sections such that only a portion of the diffuser  16  comprises a color changing material. For example,  FIG. 2  shows the lighting fixture  10  in which the diffuser  16  is separated into a first diffuser section  16 A and a second diffuser section  16 B. The first diffuser section  16 A may comprise a material that is not color changing. That is, the first diffuser section  16 A may appear to be the same color regardless of whether it is primarily front-lit or back-lit. The second diffuser section  16 B may comprise a color changing material as discussed above. In some embodiments, the light source  14  may include a first light source  14 A and a second light source  14 B. The first light source  14 A may provide light towards the area of interest through the first diffuser section  16 A, while the second light source  14 B may provide light towards the area of interest through the second diffuser section  16 B. To ensure that light from the first light source  14 A is provided through the first diffuser section  16 A and light from the second light source  14 B is provided through the second diffuser section  16 B, dividers  24  may be used to direct light from the first light source  14 A through the first diffuser section  16 A and from the second light source  14 B through the second diffuser section  16 B. 
     In some embodiments, the control circuitry  20  may be capable of independently controlling the first light source  14 A and the second light source  14 B. Breaking the diffuser  16  into the first diffuser section  16 A and the second diffuser section  16 B and independently controlling the light provided through the first diffuser section  16 A and the second diffuser section  16 B may allow the lighting fixture  10  to more easily continue to provide light suitable for general illumination while also conveying information to individuals around the lighting fixture  10  by changing the color of the second diffuser section  16 B. For example, light for general illumination can be provided from the first light source  14 A through the first diffuser section  16 A, while the second light source  14 B can be used to change the color of the second diffuser section  16 B by changing one or more characteristics of the light emitted therefrom in order to convey information to individuals around the lighting fixture  10 . 
     The control circuitry  20  may be configured to adjust one or more characteristics of light provided from the first light source  14 A along with the one or more characteristics of the light provided from the second light source  14 B in order to maintain one or more characteristics of the overall light provided by the first light source  14 A and the second light source  14 B within the area of interest at a constant level. For example, if a brightness of the light provided from the second light source  14 B is reduced to darken the second diffuser section  16 B in order to change the appearance of the lighting fixture  10  and/or convey information to individuals around the lighting fixture  10 , a brightness of the light provided from the first light source  14 A may be increased to compensate for the reduction in the light output from the second light source  14 B and thus maintain the overall brightness of the light within the area of interest at a constant level. In this way, the appearance of the lighting fixture  10  can be changed for aesthetic purposes or to convey information while maintaining light suitable for general illumination and thus not disrupting individuals around the lighting fixture  10 . 
       FIG. 3  shows the lighting fixture  10  according to an alternative embodiment of the present disclosure wherein the first light source  14 A is arranged such that light provided therefrom is provided towards the area of interest indirectly instead of through the diffuser  16 . In such an embodiment, the entirety of the diffuser  16  may comprise a color changing material as discussed above.  FIG. 3  is provided to show that there are a number of different configurations for the light source  14  in the lighting fixture  10  in order to accomplish the objectives discussed herein. All of these configurations are contemplated by the present disclosure. 
     In some embodiments, the diffuser  16  may comprise an array of diffusers and the light source  14  may comprise an array of LEDs. Accordingly,  FIG. 4  shows the diffuser  16  as an array of diffusers  26  and the light source  14  as an array of LEDs  28 . In  FIG. 4 , each one of the array of LEDs  28  corresponds to one of the array of diffusers  26  (e.g., in a one-to-one relationship) such that light from the one of the array of LEDs  28  is provided through the one of the array of diffusers  26 . In some embodiments, more than one of the array of LEDs  28  may correspond to each one of the array of diffusers  26  (e.g., in a many-to-one relationship). In general,  FIG. 4  illustrates a relationship between LEDs  28  and diffusers  26  wherein light provided through each one of the array of diffusers  26  is individually controllable. This may be achievable, for example, using dividers  30  as shown in the lighting fixture  10  in  FIG. 5 , which shows the light source  14  including the array of LEDs  28  and the diffuser  16  as the array of diffusers  26 . As shown, the dividers  30  channel light from each one of the array of LEDs  28  into a corresponding one of the array of diffusers  26 . As discussed above, the control circuitry  20  may be configured to individually control one or more light output characteristics of the light provided by each one of the array of LEDs  28 . Accordingly, the lighting fixture  10  may provide a low resolution display surface in which information can be conveyed by changing the color of a number of the array of diffusers  26  to provide a pattern, as illustrated in  FIGS. 6A and 6B . 
     In particular,  FIGS. 6A and 6B  show a bottom-up view of the diffuser  16  and illustrate what is possible if the array of diffusers  26  includes a large number of diffusers  26  and the light provided through each one of the array of diffusers  26  is individually controllable. Patterns can be provided on the array of diffusers  26  that communicate information such as directions ( FIG. 6A ), the availability of a resource in the environment ( FIG. 6B ), or the like to individuals around the lighting fixture  10 . As discussed above, one or more light output characteristics of each of the array of LEDs  28  can be adjusted both to change the color of various ones of the array of diffusers  26  as well as maintain one or more light output characteristics in the area of interest at a constant level. For example, while a brightness of the light provided from the ones of the array of LEDs  28  corresponding with the ones of the array of diffusers  26  that are shaded in  FIGS. 6A and 6B  may be reduced to darken these ones of the array of diffusers  26 , a brightness of the light provided from one or more other LEDs  28  in the array of LEDs  28  may be increased to compensate for this reduction in brightness and thus maintain the overall brightness of the light provided by the lighting fixture  10  within the area of interest at a constant level. 
     In some embodiments, the lighting fixture  10  may include a diffuser overlay  32  on the diffuser  16  as illustrated in  FIG. 7 . The diffuser overlay  32  may prevent light from the light source  14  from reaching the portion of the diffuser  16  on which the diffuser overlay  32  is provided. The diffuser overlay  32  may be provided in a desired pattern such that when the diffuser  16  is back-lit by the light source  14  the portion of the diffuser  16  on which the diffuser overlay  32  is provided appears to be a different color than the remaining portion of the diffuser  16 . Notably, since the diffuser  16  is black or dark grey when it is not back-lit as discussed above, the pattern provided by the diffuser overlay  32  is not visible when the diffuser  16  is not back-lit by the light source  14 . This may avoid distraction or disruption when the light source  14  is not providing light through the diffuser  16 , as the pattern will not be visible. In lighting fixtures  10  such as the one shown in  FIGS. 2 and 3 , the lighting fixture  10  can continue to provide light for general illumination when the pattern is not visible. 
       FIG. 8  is a flow diagram illustrating a method for operating a lighting fixture according to one embodiment of the present disclosure. The lighting fixture discussed with respect to  FIG. 8  may be any of the lighting fixtures discussed above. First, light is provided from a light source through a diffuser towards an area of interest (block  100 ). The diffuser may comprise a color changing material as discussed above such that the diffuser appears to be a first color when primarily front-lit and appears to be a second color when primarily back-lit. In an optional step, light may be provided from an additional light source towards the area of interest (block  102 ). One or more characteristics of the light provided from the light source are changed in order to change a color of the diffuser (block  104 ). As discussed above, the color of the diffuser may be used to change the aesthetic appearance of the lighting fixture, to simulate an outdoor environment, or to convey information to individuals around the lighting fixture. In another optional step, one or more characteristics of light provided from the additional light source are changed to offset changes in the one or more characteristics of the light from the light source such that one or more characteristics of the overall light within the area of interest remain constant (block  106 ). As discussed above, this may involve decreasing a brightness of the light source to change a color of the color changing diffuser while increasing a brightness of the additional light source to offset the decrease in brightness of the light source. In doing so, light suitable for general illumination can be maintained and disruptions to individuals around the lighting fixture can be avoided. 
     As discussed above, the concepts discussed herein may be useful for communicating information via a lighting fixture while still providing light suitable for general illumination from the lighting fixture. Accordingly, individuals around the lighting fixture may not be disrupted. Any desired information can be conveyed from the lighting fixtures discussed herein. For example, binary information can be conveyed simply by changing a color of all or a portion of a diffuser as discussed above. Non-binary information may also be conveyed by changing the color of all or a portion of a diffuser in a linear or non-linear manner. Further, additional information can be conveyed when using an array of diffusers or a diffuser overlay as discussed above. 
     Exemplary information that may be conveyed from a lighting fixture or lighting fixtures includes information regarding the availability of a resource such as a cashier in a grocery store, a bathroom stall, a table at a restaurant, a parking spot in a parking garage, and the like, information regarding an emergency situation such as the location of an exit, the occurrence of an emergency, or the like, information related to directions within a space such as directions through a space (leading an individual to a desired location in a space by changing the color diffusers within several lighting fixtures along a desired path), controlling foot traffic (e.g., in a crowded public space such as a theme park, museum, hospital, etc.), information related to a request for services (e.g., the presence of an individual at a help desk, a flight attendant call), or any other information. In some embodiments, the information is determined by the lighting fixture  10  itself (e.g., via the control circuitry  20 ). The information may be determined using sensor data from the one or more sensors  22 , which is processed by the control circuitry  20 . In other embodiments, the information is received by the lighting fixture  10  from a remote device. 
     Further as discussed above, the concepts discussed herein may be useful for simulating outdoor environments with a lighting fixture. In particular, a color of a diffuser on the lighting fixture may be changed to better simulate certain outdoor environments such as overhead clouds and night skies. In various embodiments, these changes may be made in order to change the look of a lighting fixture throughout the day in order to align with circadian rhythms. 
       FIG. 9  shows details of the control circuitry  20  according to one embodiment of the present disclosure. The control circuitry  20  includes a memory  34 , processing circuitry  36 , communications circuitry  38 , and driver circuitry  40 . The memory  34  stores instructions, which, when executed by the processing circuitry  36  cause the lighting fixture  10  to accomplish any and all of the functionality discussed above. The communications circuitry  38  allows the lighting fixture  10  to communicate with remote devices such as other lighting fixtures, controls (e.g., wall switches and the like), and user devices (e.g., computers and portable electronic devices) in order to change one or more light output characteristics of the lighting fixture  10 , change a color of one or more diffusers, or the like. The communications circuitry  38  may enable cooperation with and coordinated operation with other lighting fixtures. The driver circuitry  40  may receive power from the power source  18  and perform any necessary conversion or conditioning to provide drive signals for the light source  14  in order to control one or more light output characteristics thereof. 
     Those skilled in the art will recognize improvements and modifications to the preferred embodiments of the present disclosure. All such improvements and modifications are considered within the scope of the concepts disclosed herein and the claims that follow.