LIGHT FIXTURE WITH UV DISINFECTION

A light fixture includes a housing forming a cavity to permit airflow therethrough. A filter is disposed within the airflow of the cavity. An ultraviolet light emitting diode is disposed within the cavity and is directed to concurrently treat the airflow and the filter to destroy biomaterial therein.

TECHNICAL FIELD

The present disclosure generally relates to disinfection and sanitization, and more particularly, to the disinfection and sanitization of air from ultraviolet light source incorporated into the light fixture.

BACKGROUND

Ultraviolet disinfection systems are known and have a successful history of use in the reduction of viable concentrations of bacteria, viruses, protozoa, and fungi. The core unit of these ultraviolet systems is/are a source(s) of ultraviolet radiation having wavelength(s) close to the absorption peaks of biologically significant molecules of DNA, RNA, and proteins. The system can disinfect a medium, such as water, air, or surface, to a safe condition as long as the irradiance from the ultraviolet source and the exposure time are sufficient to create a high enough disinfection dose to modify and/or destroy the internal molecular structure of the pathogens. The vast majority of known ultraviolet disinfection systems typically use mercury lamps, xenon arc lamps, excimer lamps, or UV light emitting diodes (LED) as a source of ultraviolet radiation.

Low-pressure and medium-pressure mercury lamps provide a linear spectrum of radiation with wavelengths that are in the relative vicinity to a DNA absorption spectrum. UV LEDs provide a relatively narrow spectrum of radiation of approximately 5 nm to approximately 20 nm, such that the peak of the spectrum of radiation can be further tuned to have wavelength values in the vicinity or close to one of peak DNA absorption wavelength values. UV LED light sources frequently provide the flexibility of design and features lacking in mercury lamps, xenon arc lamps, and excimer lamps. Ultraviolet light emitting sources provide a convenient and effective way for the disinfection of surfaces. However, installing a new ultraviolet light emitting system in common high occupancy facilities such as classrooms, office conference rooms, medical facility lobbies, and restaurants may have high associated costs related to mounting ultraviolet sources at different locations within a facility, providing electrical wiring and power to such ultraviolet sources and providing means for controlling these sources.

Accordingly, there is a need to reduce costs associated with installing these sources by providing ways to retrofit existing light emitting sources with ultraviolet light emitting capability. The present disclosure provides systems and methods that address various problems associated with the deployment of ultraviolet light emitting sources for the disinfection of surfaces.

SUMMARY

Consistent with a disclosed embodiment, a light fixture is provided. The light fixture may include an ultraviolet radiation source comprising at least one ultraviolet light emitting diode configured to generate ultraviolet radiation. Further, the light fixture may include a housing that further includes a cavity through which the airflow is directed by the fan. The cavity can include at least one air filter. The at least one air filter can include a HEPA equivalent filter. The at least one air filter can include a dust prefilter and/or a porous PTFE filter. The at least one air filter can be irradiated by ultraviolet radiation. The housing further comprises ultraviolet light emitting diodes positioned within the cavity to irradiate the air filter.

Consistent with a disclosed embodiment, a light fixture is provided. The light fixture may include an ultraviolet radiation source comprising at least one ultraviolet light emitting diode configured to generate ultraviolet radiation. Further, the light fixture may include a reflector being reflective (but not transparent) to the ultraviolet radiation, the reflector having a top surface, the top surface comprising a distant region and an adjacent region, wherein at least a portion of the adjacent region is located close to and below the ultraviolet radiation source, and wherein the distant region comprises a rim located above a top-most emitting point of the ultraviolet radiation source, the reflector having at least partially reflective surface with reflectivity of at least 80% in the ultraviolet region, the reflector having a visible illumination light source in proximity to a bottom surface.

Consistent with another disclosed embodiment, a light fixture is provided. The light fixture may include an ultraviolet radiation source comprising at least one ultraviolet light emitting diode configured to generate germicidal ultraviolet radiation. Further, the light fixture may include a reflector being not transparent to the ultraviolet radiation, the reflector comprising a top surface, the top surface including a first surface adjacent to the source and a second surface adjacent to the first surface, wherein every point of the second surface is located either at the same level or above every point of the first surface, wherein the reflector is configured to reflect the ultraviolet radiation above the reflector, in a volume containing air. Also, the light fixture may include a fan configured to direct the air exposed to the ultraviolet radiation from the volume towards a region located underneath the reflector, wherein an operation of the fan is selected such that an airflow resulted from the operation of the fan is such that at least some of the air located in the volume acquires a target dose of the ultraviolet radiation.

Consistent with another disclosed embodiment, a system of light fixtures is provided. Each light fixture may include an ultraviolet radiation source comprising at least one ultraviolet light emitting diode configured to generate ultraviolet radiation, and a reflector being reflective (but not transparent) to the ultraviolet radiation, the reflector having a top surface, the top surface comprising a distant region and an adjacent region, wherein at least a portion of the adjacent region is located close to and below the ultraviolet radiation source, and wherein the distant region comprises a rim located above a top-most emitting point of the ultraviolet radiation source, the reflector having at least partially reflective surface with reflectivity of at least 70% in the ultraviolet region, the reflector having a visible illumination light source in proximity to a bottom surface. Further, the light fixture may include a controller for controlling aspects of operation of any one of the plurality of light fixtures, wherein the controller is configured to control at least one of an intensity of radiation of the at least one light emitting diode, or an operation of the fan.

Consistent with another disclosed embodiment, a light fixture is provided. The light fixture may include an ultraviolet radiation source comprising at least one ultraviolet light emitting diode configured to generate ultraviolet radiation. Further, the light fixture may include a reflector being not transparent to the ultraviolet radiation, the reflector comprising a top surface, the top surface including a first surface adjacent to the source and a second surface adjacent to the first surface, wherein every point of the second surface is located either at the same level or above every point of the first surface, wherein the second surface includes a rim comprising a closed curve with points of the rim being higher than any points of the first or the second surface, or any emitting point of the ultraviolet radiation source.

In another embodiment, a light fixture includes an ultraviolet radiation source having at least one ultraviolet light emitting diode configured to generate an ultraviolet radiation, a reflector being not transparent to the ultraviolet radiation, the reflector has a top surface, the top surface including a first surface adjacent to the source and a second surface adjacent to the first surface, wherein every point of the second surface is located either at the same level or above every point of the first surface, wherein the second surface includes a rim comprising a closed curve with points of the rim being higher than any points of the first or the second surface, or any emitting point of the ultraviolet radiation source. The reflector is configured to expose an air region to a target dose of the ultraviolet radiation. A fan is configured to direct the air exposed to the ultraviolet radiation within the air region towards a region located underneath the reflector, wherein exposing the air region to the target dose of the ultraviolet radiation is achieved by selecting a fan speed and an intensity of the ultraviolet radiation within the air region.

In other embodiments, at least one ultraviolet light emitting diode emits light with an angular distribution having a half-width at half-maximum angle in a range of 10 to 60 degrees. A housing having a length, height and width dimensions, can include a left and a right side, a bottom side, and a top side, wherein the left and the right side have an area of the length times the height a first set of light emitting diodes adjacent to the left side of the housing and a second set of light emitting diodes adjacent to the right side of the housing. In one embodiment, the length of the housing is at least five times larger than the height or the width of the housing. The reflector may be adjacent to the bottom side of the housing. The light fixture can be suspended from a ceiling of a room by an element attached to the top side of the housing. The housing can include a fan configured to receive air from the top side of the housing and direct a flow of air towards a floor of a room. The reflector can be configured to prevent light emitted from the at least one ultraviolet radiation source to illuminate any portion of a room, in which the light fixture is located below the rim of the reflector.

A controller can be employed to control an intensity of radiation of at least one light emitting diode or an operation of a fan. The controller can be configured to control the intensity of radiation of the at least one light emitting diode, or an operation of the fan based on a dimension of a room in which the light fixture is installed. The controller can be configured to control the intensity of radiation of the at least one light emitting diode, or an operation of the fan based on a number of people present in a room in which the light fixture is installed. The controller can be configured to control the intensity of radiation of the at least one light emitting diode, or an operation of the fan based on a number of people present in a room in which the light fixture is installed.

The light fixture can be configured to have airflow in a vicinity of the fixture, wherein a moving parcel of air in a volume above the reflector receives a target radiational dose prior to exiting the volume, wherein the volume has dimensions of a length, a height, and a width, wherein the length is at least a length of the light fixture, and a width is at least a foot, and a height is a smallest one of a foot or a distance between the light fixture and a ceiling. A first distance from a rim of a reflector to the at least one ultraviolet light emitting diode can include a distribution of ultraviolet radiation above the light fixture such that a volume having a highest radiational intensity is located in at least one region positioned between one and five first distances from the at least one ultraviolet light emitting diode. The volume can have a highest radiational intensity about as long as the light fixture. The intensity of the ultraviolet radiation within the air region can be determined by an ultraviolet intensity emitted by ultraviolet radiation sources and angular distribution of the ultraviolet intensity emitted by ultraviolet radiation sources. The intensity of the ultraviolet radiation within the air region can be based on a shape of the reflector.

The present embodiments provide systems and methods for upper room and air disinfection. The system includes a light fixture which includes an ultraviolet radiation source comprising at least one ultraviolet light emitting diode configured to generate ultraviolet radiation. The light fixture also includes a reflector being not transparent to the ultraviolet radiation, the reflector has a top surface, the top surface comprising a distant region and an adjacent region, wherein at least a portion of the adjacent region is located close to and below the ultraviolet radiation source, and wherein the distant region comprises a rim located above a top-most emitting point of the ultraviolet radiation source, the reflector having at least partially reflective surface with reflectivity of at least eighty percent in the ultraviolet region, the reflector having a visible illumination light source in proximity to a bottom surface. The light fixture includes filters, fan and at least one ultraviolet radiation source comprising at least one ultraviolet light emitting diode configured to generate ultraviolet radiation.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Reference will now be made in detail to example embodiments, including those illustrated in the accompanying drawings. The following description refers to the accompanying drawings in which the same numbers in different drawings represent the same or similar elements unless otherwise represented. The implementations set forth in the following description of the embodiments do not represent all possible implementations consistent with the invention. Instead, they are merely examples of systems and methods consistent with aspects related to the invention as recited in the appended claims. Particular aspects of the present disclosure are described in greater detail below.

Turning to figures,FIGS. 1-3show various embodiments of light fixtures with ultraviolet radiation sources, a fan and air filters, consistent with disclosed embodiments. In an example embodiment, as shown inFIG. 1, light fixture101may include UV LED board elements111configured to irradiate air located above light fixture101(e.g., a region of air109). In some cases, elements111may include optical elements (e.g., lenses, reflectors, and the like) for effectively directing UV radiation into region109. In an example embodiment, elements111may be directed to region109to result in a target sterilization of air in region109(e.g., a log sterilization of a target virus in region109). Additionally, fixture101may include one or more forced convection devices, such as, e.g., fans112configured to direct air from region109through an air filtering element115. In an example embodiment, element115may be a pleated or non-pleated porous poly-tetra-fluoro-ethylene (PTFE) filter.

In an example embodiment, fans112may be secured in place using a perforated plate113configured to transmit air. In addition to elements111, fixture101may also include additional UV LED sources117positioned and oriented to further sterilize air within an enclosure116. In an example embodiment, sources117may include reflectors, or any other suitable optical elements for irradiating air within enclosure116. In an example embodiment, internal surfaces of enclosure116may be reflective to ultraviolet radiation. For example, a lower surface of enclosure116may be a UV reflective cover131. In some cases, sources117may be directed to irradiate a low surface118of filter115. As shown inFIG. 1, air may be configured to exit through louver vents119, and be directed substantially downwards, away from light fixture101. In some cases, vents119may have adjustable openings, such as an opening150(e.g., a shape, an orientation, or a size of openings configured for transmitting air out of enclosure116may be adjustable).

In some cases, openings150and vents119can be configured to eliminate propagation of UV radiation to outside of light fixture101. As shown inFIG. 1, light fixture101may further include a white LED source (or other sources of a visible radiation), such as a white LED board132. In an example embodiment, source132may include optical elements such as lenses (e.g., a total internal reflection lens), mirrors, and the like. Further, source132may be connected to a heatsink123configured to transfer at least some of the heat generated by source132into ambient environment. As shown inFIG. 1, light fixture101may include a reflector125for directing some of the visible light generated by source132towards a diffuser127. In an example embodiment, the diffuser may be made from any suitable material that is at least partially transparent to visible radiation. The diffuser may be configured to diffuse the visible radiation of source132. The diffuser may be configured to connect to walls140A and140B via connection hooks141A and141B or the like.

In various embodiments, light fixture101may include driver electronics module121that may be placed at any suitable location within light fixture101. In an example embodiment, module121may be configured to control any of operation of fans112, UV LED sources111and117, as well as source132. In some cases, module121may be configured to adjust opening150. In various embodiments, module121may be controlled wirelessly or through wired connection via an interface of a suitable electronic device. In an example embodiment, the suitable electronic device may be a smart phone, a computer, a tablet, a touch screen, an audio processing device (e.g., ALEXA®), or any other suitable device.

FIG. 2shows an embodiment of light fixture201that may be a variation of the embodiment shown inFIG. 1. Light fixture201may include a dust pre-filter211, as well as multiple sets of UV LED sources213configured to irradiate enclosures216, as well as sides218of filter215.FIG. 3shows and example embodiment of fixture301(which may be similar to101), in which driver electronics module121is not present, at least in vicinity of source132but installed remotely and connected via wired connection. Further, consistent with the embodiment shown inFIG. 3, a bottom part of enclosure116incudes a top portion of heat sink123, allowing air within enclosure116to convectively cool heat sink123.

FIG. 4shows an example embodiment of a light fixture401including fan112configured to direct air from region109into an air duct411. Additionally, or alternatively, a second air fan412may be also present and configured to move air within duct411. In an example embodiment, multiple external UV LED sources111may be present, as described above. Further, internal UV LED sources117may be placed at different locations within light fixture401. For instance, some of sources117may be placed within air duct411, and some sources117may be placed underneath fan412. Air duct411may include walls that are reflective to ultraviolet radiation (e.g., walls having an aluminum coating, a suitable polymer coating such as a PTFE, and the like). In an example embodiment, some of sources117may be configured to irradiate a surface of an air filter415, as shown inFIG. 4.

In an example embodiment, visible light sources425may be positioned underneath filter element415and may be configured to emit light downwards from fixture401via an element417. Light sources425may be protected from UV radiation using UV protective reflectors430.

In an example embodiment, element417may be at least partially transparent to visible radiation. For instance, element417may be a visible light diffusing element. Additionally, in some cases, element417may also be transmittable to air. In an example embodiment, element417may be formed from a material that may be both transmittable to air and at least partially transparent to visible radiation and essentially not transparent to UV radiation. In some cases, element417may be an air filtering element. For instance, element417may be formed from a pleated or non-pleated porous poly-tetra-fluoro-ethylene (PTFE) filter. Additionally, or alternatively, element417may include holes for air transmission. In some cases, air may be configured to be transmitted around (e.g., around edges) of element417.

As can be seen in the Figs. and, in particular,FIGS. 1-3, the filter113and filter assemblies in accordance with the present embodiments are exposed to UV radiation duration operation of the fixtures. The filters can be exposed to UV sources above, below and in between filters and filter layers. The incident UV radiation on the filters reduces the need to clean or replace the filters over time. The filters are preferably fabricated to be UV resistant and in some embodiments are bio-resistant to bacteria, viruses, mold etc. In particularly useful embodiments, the filters can include a pleated or non-pleated porous poly-tetra-fluoro-ethylene (PTFE) filter. In one embodiment, the filter, its housing, adhesives and other components are made to be UV resistant. The filter material itself, e.g., fibrous network materials, can include a porous PTFE material. The filter may have a pleated construction to reduce pressure drop across the filter due to larger material surface area incorporated into a size of the filter. Pleating is preferably sized to permit UV wavelength radiation to destroy bioparticles over the surface of the filter. The other filters components are preferably formed from a material having similar characteristics to that prevent biomaterials from growing and provide capture efficiency of above 99% and more preferably above 99.9%. In a particularly useful embodiment, one or more filters can include a porous network that can catch and collect biomatter and material that is stable under UV irradiation such that the organic contaminant can decompose on the surface of the filter under very high cumulating UV dose capable of breaking of, for example, carbon-carbon bonds and other chemical bonds in the organic biomaterial molecules.

In some cases, one or more air filters may be used with sets of UV LED sources (e.g.,115) may be installed at any suitable location within a cavity to further sterilize air and filters within the cavity. Sources may be directed towards filter surfaces to disinfect the filters at an inlet (or outlet) of the fixture. Bio-particles are trapped by the filter and have a higher density at the inlet. The present embodiments, permit the filter to be exposed to the UV radiation and concurrently clean the filter and the surrounding air. For example, some of the sources may be directed to disinfect the dust prefilter, and other sources may be directed to disinfect or decontaminate a pleated porous PTFE filter. In an example embodiment, the porous PTFE filter may be constructed to have the most penetrating particle size (MPPS) of less than 10 microns and, more preferably, less than 0.3 micron, and, more specifically, less than 0.1 microns.

By employing, e.g., porous PTFE bound to a substrate, tensile strength and elongation at break point is increased; therefore, the useful filter life under UV irradiation is also increased. In one example, the PTFE material can not only filter less than 0.1 micron particles for greater than 99.0% efficiency but can sustain an extended or indefinite life even at high irradiation rates, e.g., hundreds of mJ/cm2under normal particle loads.

The PTFE material is stable and maintains a collection efficiency under very harsh UV exposure conditions. In useful embodiments, high UV dosages of at least 1000's of mJ/cm2to 10000's of mJ/cm2can be achieved with longer life where a dose to inactivate, e.g., the COVID-19 virus on a surface varies from 15 to 40 mJ/cm2. The UV exposed filter in accordance with the present embodiments facilitates surface disinfection in addition to direct air disinfection and can filter material while recycling UV radiation inside a cavity, since PTFE material is highly reflective in the UV spectral range. In one embodiment, the filter material can be pleated for lower pressure drop across the filter. In addition, by dispersing UV sources between filter layers, particles can be dispersed and the filters treated with UV to reduce pressure drop and ensure the destruction of pathogens. In other embodiments, other UV compatible materials and coatings may also be employed.

FIG. 5Aillustrates another example embodiment of a light fixture505of length L, including ultraviolet radiation sources510A,510B, and the like, for irradiation of upper room space, consistent with disclosed embodiments. In an example embodiment, ultraviolet radiation sources510A and510B may be ultraviolet light emitting diodes (UV LEDs) with a wavelength ranging, e.g., between 230 to 360 nanometers. In an example embodiment, the intensity of UV LED sources may range between, e.g., 1 mW and 10 W. An example single UV LED source may be a printed circuit board (PCB) with one or more UV LEDs, as well as suitable optical elements (e.g., lenses, prisms, mirrors, reflective scattering elements, and the like) and/or a protective window. An example distribution of intensity525of an illustrative UV LED source (e.g., UV LED510A) is shown inFIG. 5B, with the highest intensity illuminated at angle θ=V. In an example embodiment, most of the radiation may be within a half-angle Φm, as shown inFIG. 5B.

For example, at angle Φmultraviolet radiation may be, e.g., fifty percent, forty percent, thirty percent, twenty percent, fifteen percent, ten percent, five percent, one percent, and the like, of ultraviolet radiation at a peak value (i.e., at the angle θ). In an example embodiment, angle Φmcan be 5 degrees, 10 degrees, 15 degrees, 20 degrees, 25 degrees, 30 degrees, or few tens of the degrees, etc.FIG. 5Balso shows another angular distribution of intensity526, for which the maximum value of ultraviolet intensity may be achieved at an angle θ=θithat is larger than zero degrees (e.g., θimay be between a few degrees to a few tens of the degrees).

Returning toFIG. 5A, light fixture505may have several UV LEDs positioned on the left side and the right side of a lighting fixture housing515. For example, as shown inFIG. 5A, UV LED sources510A and510B are located on the left side. In an example embodiment, a light fixture may have a characteristic length L, as shown inFIG. 5A, and may be suspended from a ceiling using suspension members511A,511B, and the like. In an example embodiment, suspension members may be solid elements (e.g., rods) or flexible elements (e.g., wires or cables). In an example embodiment, members511A,511B may be used not only to suspend a light fixture505but also for conducting electrical power to fixture505and/or for communicating data represented by digital electrical signals to and from fixture505. In an example embodiment, fixture505may include a reflector513, which may include several surfaces such as surfaces517A and517B, shown on the left side of reflector513. Reflector513may have similar surfaces518A and518B on the right side of reflector513. In an example embodiment, reflector513may be symmetric about a midline M, as shown inFIG. 5A.

In an example embodiment, surface517B and518B may form an angle α with horizontal and be bent relative to corresponding surfaces517A and517B, as shown inFIG. 5A. The angle α may be in a range of, e.g., 0 to 60 degrees, but in some example embodiments, the angle α may be between 5 and 25 degrees. In various embodiments, the intensity of ultraviolet radiational sources (e.g., UV LEDs510A and510B) may be selected to result in air sterilization. In an example embodiment, the air sterilization may be achieved if a parcel of air receives a target radiational dose (e.g., between 0.01 W/m2and 10 W/m2).

In various embodiments, reflector513may be configured to reflect ultraviolet radiation emitted by UV LEDs towards an upper portion of a room in which light fixture505is located. For example, reflector513may be designed to ensure that no amount of ultraviolet radiation is reflected downwards towards a lower portion of the room where people may be located. In an example embodiment, reflector513may not be transparent (e.g., opaque to UV wavelengths) to the ultraviolet radiation. Reflector513may have a top surface, the top surface comprising a distant region (e.g., region517B) and an adjacent region (e.g., region517A), wherein at least a portion of the adjacent region (e.g., a region521, as shown inFIG. 5A) is located close to and below the ultraviolet radiation sources (e.g., UV LEDs510A and510B), and wherein the distant region comprises a rim (e.g., the rim may be made from edges522A and522B) located above a top-most emitting point (e.g., the top-most emitting points may be located up to region523, as shown inFIG. 5A) of the ultraviolet radiation source (e.g., source510A). In various embodiments, reflector513may have at least a partially reflective surface with reflectivity of preferably at least 80% in the ultraviolet region (i.e., at a wavelength in a range of 230-360 nm), although lower reflectivities are contemplated. As shown inFIG. 5A, light fixture505may have a visible light emitting source519adjacent to the bottom part of reflector513. Source519may be configured to emit visible light towards a bottom portion of the room for illuminating objects in the bottom portion of the room. In various embodiments, the room may be configured so that ultraviolet light radiation does not reflect significantly from the ceiling and walls of the room towards the bottom portion of the room.

It should be noted that light fixture505may have any suitable control system for controlling the intensity of ultraviolet light emitting sources. In some cases, the control system may be configured to control the distribution of ultraviolet light emitting radiation by moving either UV LEDs, moving surfaces of reflector513(e.g., in some cases, angle α may be adjusted), or moving optical elements that may be adjacent to (or part of) ultraviolet light emitting sources. While it is shown that reflector513may have several surfaces (e.g.,517A and517B in a rectangular configuration), reflector513may have any number of surfaces and may have any suitable shape for reflecting ultraviolet radiation from UV LED source towards an upper portion of the room, e.g., hexagonal-shaped, round, square, etc. In some cases, reflector513may have front surfaces531A and531B, and back surface532A and532B, as shown inFIG. 5C, with at least some of the front surfaces (e.g., surface531B and532B) bending upwards at a prescribed angle (e.g., angle β).

FIGS. 6A-6Cillustrate examples of reflector513for the light fixture, consistent with disclosed embodiments. For example,FIG. 6Ashows a reflector513having sections611A-611C from which rays612may be reflected towards a region (also referred to as a volume) of air above reflector513. In various embodiments, to ensure that ultraviolet radiation from an example source510A is not emitted at any region below reflector513, reflector513may include a rim622that may be above any other point of reflector513and may also be above the highest emitting point of source510A. For example, a vector613drawing from at least one highest emitting point of source510A may have a non-zero angle ϕ with a horizontal line611, as shown inFIG. 6A.FIGS. 6B and 6Cshow different embodiments of reflector513for different distributions of intensities525and526. In various embodiments, reflector shape513may be chosen (i.e., tailored) for particular intensity525or526emitted by source510A. The reflector shape513is not limited to the examples shown.

FIGS. 7A-7Billustrate example views of a light fixture with ultraviolet radiation sources, consistent with disclosed embodiments. In an example embodiment,FIG. 7Ashows light fixture505as viewed from the bottom of fixture505, whileFIG. 7Bshows fixture505as viewed from the side of fixture505. Fixture505includes a source of visible light519, as indicated inFIG. 7A. As shown inFIG. 7B, multiple UV light sources may be installed on housing515. As described above, such UV light sources may be PCB boards populated with UV LEDs and UV transparent optical element (e.g., lens or window). Single pass transmission of such optical elements should be preferably at least 70% or higher at the peak emission wavelength of the UV LEDs. In an example embodiment, housing515may have electrical wiring and a control system for electrically powering and controlling the operation of the UV LEDs. In some embodiments, a control system for controlling one or more light fixtures may be installed elsewhere (i.e., not within housing515of fixture505). In some embodiments, UV LED510A may be a UV LED source containing a plurality of UV LEDs. For example, UV LED510A may be a printed circuit board containing multiple UV LEDs. In some cases, multiple boards510A-510M may be installed on a side711of housing515. For example, there can be a few boards or as much as a few tens of boards.

FIGS. 8A-8Billustrate example light fixtures with airflow controlling elements811A,811B, consistent with disclosed embodiments.FIG. 8Ashows a 3-dimensional view of reflector513and housing515of light fixture505. As shown inFIG. 8A, housing515may include air controlling elements811A and811B. These elements may be, for example, forced convection devices, e.g., fans, configured to flow air from a volume821located above light fixture505towards a bottom portion of a room (i.e., below light fixture505, towards volume822, as shown inFIG. 8B). In an example embodiment, flow controlling elements811A and811B may flow air from an opening813in housing515, as shown inFIG. 8B.

FIG. 8Cshows an example light fixture505in cross-section with flow controlling elements811A-811C. Light fixture housing515may include various flow control elements839,837A-837C, and836for controlling air flow through cavity840contained in housing515. As shown inFIG. 8C, elements811A-811C may include fans, and elements836may be surfaces for controlling the flow. For example, elements836may be positioned to help increase the uniformity of air flow through the top portion851of housing515. In some cases, elements839and837A-837C may include a set of meshes or porous slabs (e.g., element839) for improving the uniformity of air flow through cavity840. In some cases, a particular distribution of air flow through surface851may be required and may be configured by positioning elements836and selecting meshes837A-837C. In some cases, meshes837A-837C may have inclined pores834, pores of variable size (e.g., sizes of pores may vary for different sections of surface851), pores of variable density throughout surface851, and the like. For example, meshes837A-837C, element839, and elements836may be configured to provide a higher air flow rate at the sides of surface851than at the center of surface851. Alternatively, the middle section of surface851may have a higher flow rate at the center of surface851. In various embodiments, elements839,837A-837C, and836, are configured to provide a required air flow rate through cavity840.

FIG. 9illustrates another example of reflector513for a light fixture, consistent with disclosed embodiments. The reflector may include multiple surfaces911A-911D, with surfaces positioned and oriented to provide a target ultraviolet radiation intensity above light fixture505. Only a left side of reflector513is shown attached to housing515, and a right side of reflector513may be formed to have the same shape, such that reflector513is symmetric about housing515. In other embodiments, the reflectors513may be asymmetric to provide a desired appearance or to fit in a selected location. Other reflector profiles are also contemplated.

As previously shown inFIGS. 8A and 8B, air controlling elements may be installed into housing515. In various embodiments, the air is obtained from a top portion of a room (e.g., from air volume821, as shown inFIG. 8A) and is moved towards a bottom portion of the room (e.g., towards air volume822, as shown inFIG. 8B). Light fixture505may be configured to irradiate volume821with ultraviolet light such that any parcel of air (i.e., any small portion of air found in volume821) is thoroughly sterilized prior to moving from volume821to volume822. Further, during airflow from volume821to volume822, air may pass through a duct (herein, also referred to as a cavity) located in housing515, as shown inFIG. 10. It should be noted that the UV radiation from sources that is reflected by the reflectors purifies the air entering any inlet filters treats the filters as well for the described embodiments.

In an example embodiment, the duct may include one or more filters. In an example embodiment, the duct may have a first filter1013that may be a dust prefilter, a high-efficiency particulate arrestment (HEPA) filter, and the like, and a second filter1015that may be a pleated or non-pleated porous poly-tetra-fluoro-ethylene (PTFE) filter. In some cases, more air filters may be used. In some cases, another set of UV LED sources1011A and1011B may be installed at any suitable location within a cavity to further sterilize air within the cavity. In some cases, sources1011A and1011B may be directed towards filter surfaces to disinfect the filters. For example, at least some of the sources (e.g., sources1011A) may be directed to disinfect the dust prefilter, and other sources (e.g., sources1011B) may be directed to disinfect or decontaminate a pleated porous PTFE filter. In an example embodiment, the porous PTFE filter may be constructed to have the most penetrating particle size (MPPS) of less than 10 microns and, more preferably, less than 0.3 micron, and more specifically, less than 0.1 microns.

FIGS. 11 and 12show an example placement of a light fixture within a room and an illustrative distribution of ultraviolet light rays throughout an upper room space, consistent with disclosed embodiments. As shown inFIG. 11, fixture505may be elongated and extend through a large portion of a room. In an example embodiment, the room may be a conference room, and fixture505may extend over a significant length of the room (e.g., 40%, 50%, 60% of the room length, and the like. In an example embodiment, fixture505may be separated from a ceiling by a distance of a few inches to a few feet. In some cases, more than a few feet may separate fixture505from the ceiling. Light fixture505may extend in a middle portion of an elongated room and be positioned at about an equal distance from various walls of the room. For larger rooms, to thoroughly disinfect the air, multiple light fixtures505may be located within a room. In an example embodiment, light fixtures505may be distributed within a room to result in the distribution of ultraviolet radiation intensity such that all the air in the upper portion of the room is thoroughly disinfected.FIG. 12shows a simulated distribution of rays from light fixture505. At least some of the rays of ultraviolet radiation reach ceiling and contributes to an ultraviolet radiation distribution1211over the ceiling. Additionally, some of the ultraviolet radiation reaches side walls of the room and contributes to an ultraviolet radiation distribution1212over the walls of the room.

Depending on the size of a room and airflow within the room, a particular shape for reflector513may be selected to produce an optimal distribution of intensity within the room. For example,FIG. 13shows an example raytracing simulation of the distribution of ultraviolet light intensity over a side wall of a room obtained using different reflectors, where the ultraviolet light may be emitted from ultraviolet light sources placed in housing515of fixture505. The ultraviolet radiation intensity (URI) as measured along a surface perpendicular to a ceiling (e.g., one of the side walls) may be smaller for a reference reflector1311, as compared to a straight reflector1312, and case1313where light fixture505has no reflector. However, some of the URI may be directed towards a ceiling, as shown, for example, inFIG. 14. As shown inFIG. 14, reflector1311redirects URI towards the upper volume of the room. In an example embodiment, for reflector1311, there are two sections,1411A and1411B, in which the URI is the highest. Such sections may be sections of air volume in which air is thoroughly disinfected. The air from these air sections may be directed by air controlling elements811A and811B (shown inFIG. 8A) towards volume822, as shown inFIG. 8B. Note that for the case of reflector1312and no reflector case1313, most of the URI is distributed sideways and the URI is not significantly redirected towards a ceiling of the room. For reflector1312and no reflector case1313, only small regions1411A and1411B are observed of relatively low intensity (e.g., URI in regions1411A and1411B is about twice as large for reflector1311as for other reflector cases1312and1313). As shown inFIG. 15, reflector1311ensures that URI is distributed into an upper portion of a room, while for reflector1312and no reflector (case1313), at least some of the URI can be found in a lower portion of the room possibly endangering people located in that portion of the room.

FIGS. 16 and 17show example distributions of ultraviolet light intensity correspondingly over a side wall of a room and a ceiling of the room obtained for ultraviolet light sources with different angular distribution of light intensity, consistent with disclosed embodiments. The distributions were obtained for a reference reflector1311. For example, for ultraviolet light sources having an angular distribution of intensity with Φm=40° (Φm, is shown inFIG. 5B), a significant amount of URI may be emitted sideways to housing515as indicated by region1611A. For the ultraviolet light sourced (e.g.,510A and510B, as shown inFIG. 5A) with Om=60°, region1611B (corresponding to region1611A) may be significantly smaller, as shown on an intensity distribution plot corresponding to a 60-degree beam angle, as shown inFIG. 16.FIG. 17shows the distribution of URI over a ceiling of a room obtained for ultraviolet light sources with different angular distribution of light intensity. For a 40-degree beam angle, the URI distribution includes high-intensity zones1711A and1711B, while for the 60-degree beam angle, the URI is more evenly distributed over a volume above light fixture505.

In some embodiments, depending on airflow, it may be preferred to have high-intensity regions for air disinfection (e.g., region1711A and1711B (FIG. 17), or1411A and1411B (FIG. 14)). For example, when there is airflow from the upper portion of the room (e.g., from volume821) to a lower portion of the room (e.g., to volume822), such regions of high intensity may be preferred. Alternatively, when there is no or little airflow in the room, a more homogeneous distribution of the intensity may be preferred.

FIGS. 18-34show other distributions of ultraviolet radiation intensity over different surfaces in a room. For example,FIGS. 18, 20, and 22show a distribution of ultraviolet radiation over the walls of a room, whileFIGS. 19, 21, 23-34show a distribution of ultraviolet radiation over the ceiling of the room. In various embodiments, the distribution depends on a type of reflector, as indicated inFIGS. 18-34, and the angular distribution of radiation intensity (ADRI) emitted by ultraviolet radiation sources (e.g.,510A and510B, as shown inFIG. 5A). In an example embodiment, a configuration of reflector and ADRI may be selected to control the location and size of high-intensity regions (e.g., region3411A, as shown inFIG. 34). For example, for reflector513, as shown inFIG. 34(60-degree angle for the slanted reflector), and ADRI characterized by the angle Φm=60, a single high intensity region3412is shown inFIG. 34, while for reflector (20-degree angle for slanted reflector,FIG. 34) and ADRI characterized by angle Φm=60, two high intensity regions3411A and3411B are shown.

As described above, light fixture505or a system associated with light fixture505may include a control module for controlling various aspects of the operation of fixture505. In an example embodiment, the control module may be configured to turn the UV LEDs off when an object is detected in an upper portion of the room. Such detection may be determined by proximity sensors or any other object detection sensors known in the art. These sensors may be installed on light fixture505or may be installed elsewhere in the room. In some cases, the control system may control more than one light fixture505that may be installed in a room. For example, the control system may be placed in a room remote from any of light fixtures505. The control system may communicate with light fixture505using any suitable means such as wired or wireless connections. The control system may be configured to adjust URI above light fixtures505to result in overall target levels of URI above light fixtures505. Furthermore, the control system may adjust the airflow rate in the room by adjusting air controlling elements811A and811B of fixtures505.

In various embodiments, the control system may include human presence sensors that may be used to detect the presence of people within a room (such presence sensors are referred to herein also as proximity sensors and may include optical sensors, infrared sensors, ultrasound sensors, sensors for detecting fluctuation of light, or any other suitable sensors capable of detecting a presence of a person). If the presence of people is detected, the control system may be configured to modulate ultraviolet radiation sources (URS) (e.g., turn off URSs to prevent irradiation of people with the UV light from URS, decrease the intensity of URS, and the like). In some cases, presence sensors may be installed elsewhere (i.e., not within light fixture505). For example, a presence sensor may be installed above light fixture505(e.g., on a ceiling). In various embodiments, at least one occupancy sensor, motion sensor, proximity sensor, and the like may be incorporated in light fixture105and may be electrically connected to the control system that may control at least one ultraviolet radiation source. In some cases, a suitable intensity monitoring sensor(s) (e.g., a fluorescent sensor) may be used to determine the intensity of irradiation over a surface. The control system may be configured to control one or more URSs (e.g., all of the available URSs), as well as occupancy sensors, motion sensors, proximity sensors, and the like, and a power supply. In an example embodiment, the control system may control ultraviolet radiation generated by the at least one ultraviolet radiation source based on the data obtained from motion sensors or intensity monitoring sensor(s). Based on received data from intensity monitoring sensor(s), the control system may adjust the intensity of various ultraviolet radiating sources (e.g., UV LEDs) to deliver targeted ultraviolet radiation to at least one designated zone within the disinfected area (e.g., a particular portion of a volume of air in an upper room region). In some cases, when UV LEDs (or other sources of UV radiation) are movable, the control system may adjust the orientation (and/or position) of these sources to deliver targeted ultraviolet radiation to at least one designated zone within the disinfected area.

In various embodiments, light fixture505may have at least one electrical connection. For example, the electrical connection may follow suspension members511A and511B. Such an electrical connection may provide a connection not only to ultraviolet light emitting sources but also to various sensors, controllers of the control system described above, and the like. Additionally, the data connection may be used for controlling various aspects of the operation of URSs. The electrical connection may be used to power light fixture505. In some cases, light fixture505may include a protective element for controlling aspects of the supplied power (e.g., the protective element may include a surge protector, a fuse, an AC-DC converter, and the like). URS may include UV LEDs electrically connected to a rectangular printed circuit board, of UV LEDs may be mounted on a flexible printed circuit board. The printed circuit board may include electrical wiring for delivering electrical power to UV LEDs.

As previously described and referring toFIG. 35, ultraviolet light emitting sources of fixture505may be controlled by a control system (herein, also referred to as a controller3532inFIG. 35). The controller3532may control URSs based on data collected by various sensors (e.g., proximity sensors).FIG. 35shows an example block diagram describing a system/process3501of controlling various aspects of UV light emitted by URSs (e.g., URS510A, as shown inFIG. 5A). Controller3532, as shown inFIG. 35, may control the amount of power from a power supply3511, control various aspects of UV radiation sources3512configured to irradiate upper room volume3523of air requiring disinfection, and change controlling parameters based on feedback data3515obtained from sensing devices3517. In an example embodiment, controller3532may control voltage or current provided by power supply3511.

In an example embodiment, the amount of electrical power provided by power supply3511is selected to obtain a required radiational dose for volume3523. The required dose may change depending on the time of the day, frequency of use of volume3523, amount of time available for irradiating volume3523, or any other suitable considerations. For example, a first dose may be used to irradiate volume3512while there are people in the room, and a second dose may be used to irradiate volume3523during nighttime (or during any longer intervals of time when people are not in the room, i.e., cannot be exposed to ultraviolet radiation). Such an approach may be adopted to ensure that people are not irradiated by ultraviolet light reflected from various surfaces (e.g., walls and a ceiling) of a room. In an example embodiment, a first dose may yield a few LOG reductions (e.g., one LOG reduction, two LOG reduction, and the like) of colony forming unit (CFU) of some pathogens, such as bacteria, or plaque forming unit (PFU) of some pathogens, such as viruses, and the like, while a second dose may yield a higher LOG reduction of pathogens. A LOG reduction is a mathematical term that is used to express the relative number of living microbes that are eliminated by disinfection. For example, a 1 LOG reduction corresponds to inactivating 90 percent of a target microbe with the microbe count being reduced by a factor of 10. The first dose may require high power and may be delivered in a relatively short interval of time (e.g., an interval of time between the use of the room). For example, the first dose may be delivered for a few seconds or a few minutes. In some cases, the first dose may be delivered in short bursts. In some cases, the delivery of the first dose may be interrupted if a person or people enters the room. In various embodiments, when volume3523is illuminated nonuniformly, a dose may be determined to be a minimal dose received by a region of volume3523.

In an example embodiment, while delivering an ultraviolet radiation dose, controller3532may continuously receive feedback data3515from various feedback components such as various proximity sensors3517(e.g., optical proximity sensors, infrared proximity sensors, ultrasound proximity sensors, and the like) as previously discussed. When feedback data3515indicates that one or more persons or equipment are detected in an upper room region, controller3532may terminate power supply to sources3512. Additionally, or alternatively, controller3532may decrease (or increase) power to sources3512based on the proximity of one or more persons to the upper room region.

In some cases, controller3532may further control other aspects of sources3512, such as the position of sources3512(for a case when sources are movable), the orientation of sources3112(for a case when sources3112are capable of rotation), focusing light for sources3112(for cases when sources3112may have movable optical elements for focusing light towards volume3123), and determination of which one of sources3112are turned on/off. In some cases, if sources3512include sources of different wavelengths, controller3532may control the distribution of wavelengths emitted by sources3512by controlling the power supply to each one of sources3512.

FIG. 36shows an example block diagram describing a system and process3601of controlling irradiation of volume3523. System3601may be a variation of system3501, as shown inFIG. 35. Controller3532may be configured to control sources3512and receive feedback data3515, as previously described. In various embodiments, controller3532may include an input/output (I/O) interface3611for communicating controlling parameters with a user3620. For example, user3620may enter commands via I/O interface3611or receive various data related to the intensity of sources3512, the performance of sources3512, or any other suitable data related to a process of irradiating volume3523. In an example embodiment, I/O interface3611may be a text or graphical interface. In an example embodiment, interface3611may include an application programming interface for interacting with an application installed on a device of user3620. For example, user3620may monitor data received from controller3532on a smartphone, laptop, tablet, computer, and the like, and may enter data via a graphical interface provided by the application.

Controller3532may continuously monitor data3515via module3612. Further, controller3532may control a dose of ultraviolet radiation via programmable dose module3614. In an example embodiment, module3614may receive instructions on the required dose via I/O interface3611, determine the duration of time and power levels for delivering the required dose of ultraviolet radiation to volume3523, and, via power supply3511, adjust power for sources3512. In various embodiments, as previously discussed, controller3532may monitor feedback data3515regarding the presence of people/equipment in an upper room region and adjust the supplied power to ensure that the people are not exposed to the ultraviolet radiation. Additionally, controller3532, via module3612, may monitor the electrical performance of sources3512and when electrical parameters of ultraviolet radiation sources3512change (e.g., a resistance of a circuit related to sources3512changes, a current for sources3512changes when a power supply is a voltage supply source, voltage for sources3512changes when a power supply is a current source), controller3532may be configured to adjust power supply parameters to ensure that the required dose of radiation is delivered to volume3523. For example, if a current delivered to sources3512drops (e.g., when one of UV sources3512malfunctions and current stops flowing through that source), controller3532may be configured to increase supplied voltage to increase power to sources3512to offset power loss due to loss of one of UV sources3512.

Controller3532may implement a delay Δt for increasing the supplied voltage. Similarly, if a power supply is a current source, the current may be adjusted (increased or decreased) to result in a required dose for irradiating volume3523, if one or more sources3512fail. In some cases, the performance of sources3512may continuously degrade with time requiring continuous adjustments for supplied power by controller3532in order to maintain the required dose for irradiating volume3523. Besides adjusting power supply, controller3532may be configured to adjust other aspects of the operation of sources3512. For example, as described above, if sources3512are movable or rotatable, controller3532may move or rotate sources3512. Additionally, or alternatively, controller3532may control the distribution of ultraviolet light intensity over volume3523by turning on/off individual one of or a few sources3512or adjusting power to one of or a few sources3512. Furthermore, controller3532may control the airflow controlling elements811A and811B (FIG. 8A-C). For instance, controller3532may control the volume of air moved by these elements. In various embodiments, sensing devices3517may include airflow sensors, and controller3532may include data obtained from such airflow sensors to adjust operations of elements811A and811B.

In various embodiments, controller3532may include a processor for processing data3515and electrical data from sources3512(e.g., voltage and current data needed to power sources3512), and memory storage3615for storing various instructions related to doses for irradiating volume3523, and for storing any other suitable data (e.g., historical data related to irradiation of volume3523, such as historical data3515, dates and times of when ultraviolet radiation dose was delivered to volume3523, or any other relevant historical data). Memory storage3615may receive data from a communication interface3613, where interface3613may be configured to collect data from module3612, I/O interface3611, and programmable dose module3614. In some cases, storage3615may provide stored data to interface3613. Interface3613may communicate with facility controller3615to provide various data related to irradiation of volume3523.

In an example embodiment, facility controller3615may be a cloud based service that may be configured to collect data received from interface3613. In some cases, facility controller3615may combine data from various sets of ultraviolet sources3512. Furthermore, facility controller3615may collect data from different light fixtures505available within a given room (facility). For example, if a facility is a restaurant, facility controller3615may be configured to collect radiational data from a plurality of light fixtures505for the upper room region of the air. In some cases, when a facility is a medical facility, data about UV doses for different rooms, room geometries, number of fixtures505in a room, distances from fixtures505and room walls and ceiling, etc., may be transmitted to facility controller3615and further processed by controller3615. In some cases, controller3615may be configured to display data, deliver data to different devices, and/or facilitate analysis of data.

The foregoing description has been presented for purposes of illustration. It is not exhaustive and is not limited to precise forms or embodiments disclosed. Modifications and adaptations of the embodiments will be apparent from a consideration of the specification and practice of the disclosed embodiments. For example, while certain components have been described as being coupled to one another, such components may be integrated with one another or distributed in any suitable fashion. The fixtures described herein may have features that are integrated in any combination. The fixtures may be employed in rooms, vehicles, aircrafts or any other volume or space.

Other embodiments will be apparent from a consideration of the specification and practice of the embodiments disclosed herein. It is intended that the specification and examples be considered as an example only, with a true scope and spirit of the disclosed embodiments being indicated by the following claims.