Disinfecting lighting device

Abstract

Methods, systems, and devices for inactivating microorganisms are disclosed. An example method comprises emitting, with a first light source, a first light comprising a first correlated color temperature (CCT), emitting, with a second light source, a second light comprising a second CCT and, varying respective power levels of the first light source and the second light source such that the first light and the second light combine to form white light comprising an intensity associated with light in a 380-420 nanometer (nm) wavelength range sufficient to initiate inactivation of microorganisms on the surface and a third CCT between the first CCT and the second CCT.

Description

TECHNICAL FIELD DISCLOSURE

The present disclosure concerns a light-emitting device capable of emitting light that can be perceived as white or a hue of white, and more particularly, a light-emitting device capable of emitting light that can be perceived as white or a hue of white while simultaneously causing the inactivation of microorganisms.

BACKGROUND OF THE DISCLOSURE

Light-emitting devices are a primary requirement in most indoor occupied environments to provide illumination of the area, of tasks being completed in the area, and of the area's occupants and objects. Lighting technologies range widely for use indoors, from incandescent and halogen bulbs, to fluorescent and light-emitting diode (LED) bulbs and devices, among many other technologies. The primary purpose of these lighting technologies to date is to provide light that can be observed by humans as what is considered “white” light, which can effectively illuminate different colors, textures, and features of objects in a manner pleasing to humans.

While many technologies are commercially used in lighting, LED lighting is growing as a technology to provide efficient, high quality white light illumination at an effective cost point. Some common LEDs for general illumination use a semiconductor junction that is energized to emit blue light and that is combined with a phosphor material, such as cerium-doped yttrium aluminum garnet (YAG:Ce) to convert a portion of that blue light to other wavelengths of light, such as yellow wavelengths. When balanced properly, the combined light emitted from the semiconductor junction and the phosphor material is perceived as white or a hue of white. Blue light-emitting semiconductors are used currently for many reasons, including relatively high efficiency, relatively low cost, and relatively desirable color benefits of the blue light contribution to the overall spectrum of light (as compared to light-emitting semiconductors that emit light of another color).

Some alternative LED technologies use semiconductor junctions that emit UV, near UV, or violet light instead of blue light. A phosphor material is combined to convert a portion of the blue, violet, or UV light to other wavelengths of light and the two components are balanced appropriately to provide white or a hue of white light. Violet LEDs are used less frequently due to typically lower efficiency and cost performance, but have commercially been shown to be able to provide an adequate visual quality of light in some characteristics like the Color Rendering Index (CRI).

With both of these LED technologies, achieving a relatively high luminous efficacy of emitted radiation is balanced against achieving desirable color characteristics (CRI, correlated color temperature (CCT), Gamut, etc.) of the emitted radiation. In other words, the wavelength of combined light emitted from the lighting device is chosen, in relation to the spectral sensitivity of the human eye, to achieve high efficiency, while minimizing the sacrifice of desired color characteristics.

Alternative light sources have been created with additional performance factors in mind that utilize emitted light in different manners. Lighting fixtures and devices for horticulture, health, warmth, and disinfection have been demonstrated. In addition to being tuned for luminous efficacy of radiation, these lighting fixtures and devices are tuned to provide increased outputs of certain regions of radiation to accomplish the additional performance factor.

These lighting fixtures and devices provide a dual or multiple function of lighting through the use of various alternative functions of light such as photochemical, photobiological, radiant energy, and others. Typically, radiant energy outputs are attempted to be optimized for specific regions matching absorption or activation spectrums of the added function. For example, light fixtures and devices for horticulture are attempted to be optimized for emitting light matching absorption or activation spectrums of chlorophyll and other plant based photo-activated mechanisms. Light fixtures and devices for assisting circadian rhythm are attempted to be optimized for emitting light matching absorption or activation spectrums of melatonin.

In these lighting fixtures and devices that emit light for multiple functions, the light emissions can be balanced to achieve an acceptable level of each function. One of the functions can be general illumination (e.g., when the multiple-function lighting fixtures and devices are used in spaces occupied by humans), in which case, achieving a relatively high luminous efficacy of the emitted light is balanced not only against achieving desirable color characteristics of the emitted light, but also of achieving the one or more other functions to an acceptable or desired level.

BRIEF DESCRIPTION OF THE DISCLOSURE

Embodiments of the disclosure disclosed herein may include a device which inactivates microorganisms, the device including a light emitter and at least one light converting material arranged to convert at least a portion of light from the light emitter, wherein any light emitted from the light emitter and the at least a portion of converted light emitted from the at least one light-converting material mixes to form a combined light, the combined light having a proportion of spectral energy measured in an approximately 380 nm to approximately 420 nm wavelength range of greater than approximately 20%.

Embodiments of the disclosure herein may include a device which inactivates microorganisms, the device including a light emitter and at least one light-converting material arranged to be in a direct path of the first light. The light emitter is configured to emit a first light within a range of 380 nm to 420 nm, and the at least one light-converting material is configured to emit a second light in response to the first light being incident on the at least one light-converting material. The first light exiting the device and the second light exiting the device mix to form a combined light, the combined light being white. The at least one light-converting material includes at least one optical brightener which emits light in the wavelength range of 440 nm to 495 nm.

Embodiments of the disclosure disclosed herein may include a light emitting device comprising at least two light emitters, wherein the at least two light emitters are configured to emit light having a same wavelength in the range of 380 nm to 420 nm; each of the at least two light emitters includes a light-converting material arranged to be in a direct path of the light emitted from a given light emitter; each light-converting material being arranged to convert the wavelength of the light emitted from the given light emitter to a wavelength different therefrom; and the light emitted from each of the light-converting materials combines to form white light.

Embodiments of the disclosure herein may include a light emitting device comprising at least two light emitters, wherein the at least two light emitters are configured to emit light having a same wavelength in the range of 380 nm to 420 nm; one or more of the at least two light emitters includes a light-converting material arranged to be in a direct path of the light emitted from a given light emitter; each light-converting material being arranged to convert the wavelength of the light emitted from the given light emitter to a wavelength different therefrom with the exception that the wavelength of light emitted from at least one light emitter is not converted to a wavelength different therefrom; and the light from any light emitter not passing through a light-converting material combines with the light emitted from each of the light-converting materials to form white light.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of the disclosure will be more readily understood from the following detailed description of the various aspects of the disclosure taken in conjunction with the accompanying drawings that depict various aspects of the disclosure.

FIG. 1 illustrates a light-emitting device according to various embodiments (the light-emitting device including a light emitter, and a light-converting material contained by an encapsulant).

FIG. 2 illustrates another light-emitting device according to various embodiments (the light emitting device including a light emitter, and a light-converting material contained by a lens).

FIG. 3 illustrates another light-emitting device according to various embodiments (the light emitting device including an array of light emitters with a light-converting material thereover).

FIG. 4 illustrates another light-emitting device according to various embodiments (the light emitting device including an array of light emitters with a different light-converting material over each light emitter).

FIG. 5 illustrates another light-emitting device according to various embodiments (the light emitting device including a light emitter and a light-converting material contained by an encapsulant).

FIG. 6 illustrates another light-emitting device according to various embodiments (the light emitting device including a light emitter and light-converting material contained by a lens).

FIG. 7 illustrates another light-emitting device according to various embodiments (the light emitting device including a light emitter and conformal light-converting material contained by a lens).

FIG. 8 illustrates another light-emitting device according to various embodiments (the light emitting device including an array of light emitters and a light-converting material contained by an encapsulant).

FIG. 9 illustrates another light-emitting device according to various embodiments (the light emitting device being in the form of a light bulb including a light emitter and an outer light-converting filter).

FIG. 10 illustrates another light-emitting device according to various embodiments (the light emitting device being in the form of a light bulb including a light emitter and a light-converting filter contained by an outer bulb).

FIG. 11 illustrates another light-emitting device according to various embodiments (the light emitting device being in the form of a light bulb including a light emitter and a light-converting filter on top of the light emitter).

FIG. 12 illustrates another light-emitting device according to various embodiments (the light emitting device being in the form of a light bulb including a light emitter and a light-converting filter surrounding the light emitter).

FIG. 13 illustrates another light-emitting device according to various embodiments (the light emitting device being in the form of a spot lamp including a light emitter, a light-converting filter on the light emitter and a lens).

FIG. 14 illustrates another light-emitting device according to various embodiments (the light emitting device being in the form of a spot lamp including a light emitter, a light-converting filter not in contact with the light emitter but in contact with a lens).

FIG. 15 illustrates another light-emitting device according to various embodiments (the light emitting device being in the form of a spot lamp including a light emitter and a light-converting filter not in contact with the light emitter).

FIG. 16 illustrates an ANSI C78.377A LED standards with accepted x,y coordinates at selected CCTs that are color coordinate ranges for light-emitting devices in some embodiments of the disclosure.

FIG. 17 illustrates a light-emitting device having all violet light emitters wherein at least one of the emitters remains uncovered by a light-converting material.

FIG. 18 illustrates another light-emitting device having all violet light emitters wherein all of the emitters have a light-converting material arranged thereover.

FIG. 19 illustrates another light-emitting device, similar to that of FIG. 18 but with a lens containing the light-converting material.

FIG. 20 illustrates another light-emitting device, similar to that of FIG. 18 but with an encapsulant containing the light-converting material.

FIG. 21 illustrates an ANSI C78.377-2017 white light standards with accepted x-y coordinates at selected CCTs that are color coordinate ranges for light-emitting devices in some embodiments of the disclosure.

It is noted that the drawings may not be to scale. The drawings are intended to depict only typical aspects of the disclosure, and therefore should not be considered as limiting the scope of the disclosure. In the drawings, like numbering represents like elements between the drawings. The detailed description explains embodiments of the disclosure, together with advantages and features, by way of example with reference to the drawings.

DETAILED DESCRIPTION OF THE DISCLOSURE

According to various embodiments, a lighting device is disclosed that is capable of emitting light that can be perceived as white or a hue of white and simultaneously is capable of emitting certain concentrations of light with specific wavelengths that are associated with the inactivation of at least some microorganisms.

The light-emitting device is composed of a light emitter (e.g., LEDs, OLEDs, semiconductor dies, lasers), or in some cases two or more light emitters, and one or more light-converting materials (e.g., phosphors, optical brighteners, quantum dots, phosphorescent materials, fluorophores, fluorescent dyes, conductive polymers) assembled in a manner that light emitted from a light emitter will be directed into the light-converting material(s) and at least a portion of this light directed into the light-converting material(s) will be converted by the light-converting material(s) to light having a different quality (e.g., a different peak wavelength). Light can be converted by the light-converting material(s) by absorbing the light, which energizes or activates the light-converting material(s) to emit light of a different quality (e.g., a different peak wavelength). In one embodiment, a combined light emitted by the light emitter(s) and the light-converting material(s) has a proportion of spectral energy measured in an approximately 380 nm to approximately 420 nm wavelength range of greater than approximately 20%. In another embodiment, a combined light emitted by the light emitter(s) and the light-converting material(s) is white and has one or more of the following properties: (a) a proportion of spectral energy measured in an approximately 380 nm to approximately 420 nm wavelength range of greater than approximately 10%, (b) a correlated color temperature (CCT) value of 1000K to 8000K, (c) a color rendering index (CRI) value of 55 to 100, (d) a color fidelity (R_f) value of 60 to 100, and (e) a color gamut (R_g) value of 60 to 140.

The light emitter(s) and light-converting material(s) may be assembled in many different manners, such as, but not limited to the embodiments depicted in FIGS. 1-15 and 17-20. Light emitted by the light emitter(s) and the light-converting material(s) can be modified by optics, reflectors, or other assembly components to facilitate the combined light emitted by the light-emitting device being perceived as white or a hue of white.

Referring to FIG. 1, a light-emitting device 10 is illustrated that includes a pump LED 12 as the light emitter, a light-converting material 14, an encapsulant 16, and a substrate 18. The light-converting material 104 may be dispersed within encapsulant 106. Pump LED 12 and light-conversion material 104 are supported on the substrate 108.

FIG. 2 illustrates a light-emitting device 20 that includes a packaged pump LED 22 as the light emitter, a light-converting material 24, a lens 26 containing the light-converting material 24, and a substrate or base 28.

FIG. 3 illustrates a light-emitting device 30 that includes an array of pump LEDs 32 contained by a light-converting material 34 that is evenly distributed within an encapsulant 36.

FIG. 4 illustrates a light-emitting device 40 that includes an array of LEDs 42 with light-converting materials 44 that convert light to red, green, blue, and amber light. The light-converting materials 44 are shown dispersed, or contained, in an encapsulant 46. LEDs 42 and encapsulant 46 are shown supported on a substrate 48.

FIG. 5 illustrates a light-emitting device 50 that includes LED 52 contained by a light-converting material 54 that is contained by an encapsulant 56, all of which is supported on a substrate 58.

FIG. 6 illustrates a light-emitting device 60 that includes a packaged LED 62 contained by a light-converting material 64 that is contained by a lens 66. LED 62, light-converting material 64, and lens 66 are supported by a base or substrate 68.

FIG. 7 illustrates a light-emitting device 70 that includes a packaged LED 72 contained by conformally coated light-converting material 74 that is contained by a lens 76. LED 72, light-converting material 74, and lens 76 are supported on a base or substrate 78.

FIG. 8 illustrates a light-emitting device 80 that includes an array of LEDs 82 contained by a light converting-material 84 that is contained by an encapsulant 86. LEDs 82, light-converting material 84, and encapsulant 86 are supported on a substrate 88.

FIG. 9 illustrates a light-emitting device 90 that is a light bulb including LED 92, an outer light-converting filter 94, a base 97, and a pedestal 98. Base 97 and pedestal 98 support LED 92.

FIG. 10 illustrates a light-emitting device 100 that is a light bulb including an LED 102, a light-converting filter 104 contained by an outer bulb 106, a base 107, and a pedestal 108. Light-converting filter 104 can directly contact outer bulb 106.

FIG. 11 illustrates a light-emitting device 110 that is a light bulb including an LED 112, a light-converting filter 114 on top of the pump LED 112, an outer bulb 116, a base 117, and a pedestal 118. Light-converting filter 114 can be directly on the pump LED 112.

FIG. 12 illustrates a light-emitting device 120 that is a light bulb including an LED 122, a light-converting filter 124 surrounding the pump LED 122, an outer bulb 126, a base 127, and a pedestal 128. Light-converting filter 124 can directly contact pump LED 122.

FIG. 13 illustrates a light-emitting device 130 that is a spot lamp including an LED 132, a light-converting filter 134 on pump LED 132, a reflector 135, a lens 136, and a base 137. Light-converting filter 134 can be directly on pump LED 132.

FIG. 14 illustrates a light-emitting device 140 that is a spot lamp including, an LED 142, a light-converting filter 144, a reflector 145, a lens 146 on light-converting filter 144, and a base 147. Lens 146 can be directly on light-converting filter 144.

FIG. 15 illustrates a light-emitting device 150 that is a spot lamp including an LED 152, a light-converting filter 154, a reflector 155, and a base 157.

FIG. 16 serves as an example of color coordinates and ranges of color coordinates that could be achieved in practice in some embodiments of the disclosure. More specifically, FIG. 16 illustrates an ANSI C78.377A LED Standards with accepted x-y coordinates at selected CCTs.

FIG. 17 illustrates a light-emitting device 170 that includes two light emitters 172, a light-converting material 174, and a substrate 176. Light emitters 172 and light-conversion material 174 are supported on substrate 176. While only two light emitters 172 are shown in FIG. 17, there may be three, four, five, etc. light emitters 172 present in light-emitting device 170. In the embodiment of FIG. 17, all light emitters 172 emit light having a same wavelength, for instance a same wavelength in the range of 380 nm to 420 nm. As shown in FIG. 17, one light emitter 172 includes light-converting material 174 arranged to be in a direct path of the light emitted from light emitter 172 thereunder, while the other light emitter 172 remains uncovered by a light-converting material 174. Any number of light emitters 172 present in light-emitting device 170 may include a light-converting material 174 thereover.

FIG. 18 illustrates a light-emitting device 180 that includes two light emitters 182, light-converting materials 184a and 184b, and substrate 176. The embodiment of FIG. 18 differs from FIG. 17 in that all of light emitters 182 present in light-emitting device 180 include a light-converting material 184 thereover. As also illustrated in FIG. 18, while light emitters 182 are the same, each light emitter 182 has a unique light-converting material 184 thereover, for instance light-converting material 184a over a first light emitter 182 and light-converting material 184b over a second light emitter 182, and so on. The different light-converting materials capable of use in embodiments of the disclosure are described below.

FIG. 19 illustrates a light-emitting device 190 like that of FIG. 18 with the addition of a lens 196 containing light-converting materials 194a and 194b and light emitters 192.

FIG. 20 illustrates a light-emitting device 200 like that of FIG. 18 with the addition of an encapsulant 206 containing light-converting materials 204a and 204b and light emitters 202.

FIG. 21 illustrates ANSI C78.377-2017 white light standards with accepted x,y coordinates at selected CCTs, including 7-step MacAdam ellipses, and that shows quadrangles at various color temperatures for light-emitting devices in some embodiments of the disclosure. The ANSI C78.377-2017 standard states: “The purposes of this standard are, first, to specify the range of chromaticities recommended for general lighting with solid-state lighting products to ensure high-quality white light and, second, to categorize chromaticities with given tolerances so that the white light chromaticity of the products can be communicated to consumers.” Thus, the noted ANSI standard tries to define a chromaticity range (defined as “4-step” or “7-step” Quadrangles in the CIE 1931 x,y diagram, or the CIE 1976 u′v′ diagram) for high quality white lights at different CCT values. The quadrangles set color consistency bounds so that LED to LED, or even fixture to fixture, lights look consistent. The 4-step or 7-step Quadrangles also help establish how far away from a particular CCT a light can be and still be considered that particular nominal CCT. The device disclosed enables a disinfecting white light that can fall within the bounds of the Quadrangles at various color temperatures through the precise combination of selected emitters and light converting materials as described in embodiments of this disclosure. More specifically, the combined white light emitted from a light emitting device of the present disclosure can be quantified using (x,y) coordinates falling on the CIE 1931 Chromaticity diagram. The color temperature of the combined white light can vary between 1000K to 8000K for different embodiments. The (x,y) coordinates can be determined from a measured Spectral Power Distribution (SPD) graph of the emitted white light spectrum. When graphed, these determined (x,y) coordinates will fall within the bounds of a quadrangle for the color temperature of each embodiment, and thus the combined light emitted can be defined as white light using the ANSI C78.377-2017 standard.

Though illustrated in FIGS. 1-15 as an LED, the light emitter of FIGS. 1-15 as well as FIGS. 17-20 can be any known emitter, including but not limited to a substrate and an LED (e.g., pump LED), a packaged LED, an array of LEDs, an organic LED (OLED), a spot lamp, a laser, a semiconductor die and traditional light bulbs either with an LED replacement fixture or other light bulbs. Each LED can include one or more semiconductor dies that are emitters within an LED package. The light emitter can have a peak wavelength/majority of light output in the 380-420 nm wavelength range of light.

In embodiments with multiple light emitters (e.g., an array of LEDs), the light emitters can all emit light of approximately the same wavelength. For example, the array of LEDs 32 shown in FIG. 3, the array of LEDs 42 shown in FIG. 4, the light emitters 172 shown in FIG. 17, the light emitters 182 shown in FIG. 18, the light emitters 192 shown in FIG. 19 and the light emitters 202 shown in FIG. 20 can all emit light within the range of 380-420 nm. In some embodiments, the array of LEDs 32, 42 and the light emitters 172, 182, 192, 202 can all emit light within the wavelength range of 390-415 nm, and in other embodiments 400 nm-410 nm.

Light-converting material, as used herein, constitutes a broad category of materials, substances, or structures that have the capability of absorbing a certain wavelength of light and re-emitting it as another wavelength of light. Light-converting materials should be noted to be different from light-emitting materials and light-transmitting/filtering materials. Light-emitting materials can be broadly classified as materials, substances, or structures/devices that convert a non UV-VIS-IR form of energy into a UV-VIS-IR light emission. Non ultraviolet-visible-infrared (UV-VIS-IR) forms of energy may be, and are not limited to: electricity, chemical reactions/potentials, microwaves, electron beams, and radioactive decay. Light-converting materials may be contained in or deposited on a medium, making a light-converting medium. It should be understood that light-converting materials, light-converting mediums, light-converting filters, phosphors, and any other terms regarding the conversion of light are meant to be examples of the light-converting material disclosed.

In some embodiments, the light-converting material can be a phosphor, an optical brightener, a combination of phosphors, a combination of optical brighteners, or a combination of phosphor(s) and optical brightener(s). In some embodiments, the light-converting material can be quantum dots, a phosphorescent material, a fluorophore, a fluorescent dye, a conductive polymer, or a combination of any one or more types of light-converting materials. Optical brighteners are light-converting materials (e.g., chemical compounds) that absorb light in the ultraviolet and/or violet regions of the electromagnetic spectrum, and re-emit light in the blue region. Quantum dots are nanometer sized semiconductor particles that can emit light of one or more specific wavelengths when electricity or light is applied to them. The light emitted by quantum dots can be precisely tuned by changing the size, shape and/or material of the quantum dots. Quantum dots can have varying composition and structures that allow them to be classified into different types such as core-type quantum dots, core-shell quantum dots, and alloyed quantum dots. Core-type quantum dots are single component materials with uniform internal compositions, for example chalcogenides (selenides, sulfides or tellurides) of metals like cadmium, lead or zinc (e.g., CdTe or PbS). The photo- and electroluminescence properties of core-type quantum dots can be fine-tuned by changing the crystallite size. Core shell quantum dots have small regions of a first material (core) surrounded by a second material having a wider band gap than the first material (shell) and typically offer improved quantum yield; for example, a CdSe core surrounded by a ZnS shell exhibits greater than 50% quantum yield. Alloyed quantum dots include both homogeneous and gradient internal structures and allow for tuning of both optical and electronic properties by changing the composition and internal structure without changing the crystallite size; for example, alloyed quantum dots of the composition CdS_xSe_1-x/ZnS (with 6 nm diameter) can emit light of different wavelengths by adjusting the composition. Light-converting materials can be capable of absorbing multiple different wavelengths of light and emitting multiple different wavelengths of light, in both scaled and not specifically scaled manners.

The phosphor or other light converting material may be deposited directly on the light emitter, as illustrated in at least FIGS. 1-8 and 17-20, or may be remote or further removed from the light emitter, as illustrated in at least FIGS. 9-10 and 14-15, which show a light-converting filter distanced from the light emitter. The remote phosphor configuration reduces flux density through the light-converting filter by increasing surface area of the flux. The physical separation of the light emitter and the light-converting filter, and the reduced flux can reduce the operating temperature of the light-converting filter by reducing conducted heat from the light emitter. The lower temperature of the light-converting filter reduces thermal quenching of the light output and other undesirable effects of elevated operating temperature. Light-converting materials can be deposited, for example, as conformal coatings, doped encapsulants or binder materials, and remote phosphors. The at least one light-converting material may be fully homogenized at different or identical ratios and used as a bulk mix, or the at least one light-converting materials may have some or all portions positioned or layered separately, affecting the absorption and emission of different materials that may not be compatible when mixed or that may absorb too much underlying light.

As mentioned above, the light emitter of the disclosure can include a light-converting material arranged to be in a direct path of the light emitted from a given light emitter. In other words, each light emitter can have its own independent light-converting material arranged to be in a direct path of the light emitted therefrom. This allows for independent selection of light-converting material coverage for each and every light emitter.

In some embodiments, the CRI value of the combined light output or combined emitted light from the light-emitting device (e.g., light emitted from the light emitter mixed with light emitted from the light-conversion material) can have a CRI value of at least 55, 60, 65, or 70. In further embodiments, the CRI value can be at least 80, 85, 90, or 95, plus or minus approximately 5 (allowing for a CRI value of 100).

In some embodiments, the combined light output or combined emitted light from the light-emitting device can be white light. White light can be defined as light with a correlated color temperature (CCT) value of approximately 1000 kelvin (K) to approximately 8000K, in some embodiments approximately 2000K to approximately 6000K, and in some embodiments approximately 2500K to approximately 5000K, wherein “approximately” can include plus or minus about 200K.

White light can also be defined according to a variety of other industry standards such as but not limited to: the ANSI C78.377-2017 white light standard, described above, the Fidelity Index (R_f) which provides a color fidelity value, and the Gamut Index (R_g) which provides a color gamut value. Sometimes R_f and R_g values are reported in combination as the “TM-30-15” standard. R_f represents how closely the color appearances of an entire sample set are reproduced (rendered) on average by a test light as compared to those under a reference illuminant. Thus, R_f combines the computed color differences for all test-color samples in one single average index value, and is only one aspect of color quality not considering perception/preference effects. R_g provides information about the relative range of colors that can be produced (via reflection) by a white light source. A score close to 100 indicates that, on average, the light source reproduces colors with similar levels of saturation as an incandescent bulb (2700K) or daylight (5600K/6500K).

In some embodiments, the light-emitting device can have a spectral content of light output in the 380-420 nm wavelength range of at least 10%. The spectral content of light output in the 380-420 nm wavelength range is defined as the proportion of absolute irradiance value of light having wavelengths in the range of 380-420 nm relative to the absolute irradiance value of light having wavelengths in the range of 380-720 nm. Dividing the former value by the latter value yields the % spectral content of emitted light in the 380-420 nm wavelength range. The spectral output is defined as the radiometric energy. The absolute irradiance values can be measured by any now-known or later-developed means. In some embodiments, the absolute irradiance values are measured in mW of radiometric energy.

The spectral content in the 380-420 nm wavelength range can be utilized for the inactivation of bacterial pathogens. A 405 nm peak wavelength and a range of wavelengths above and below 405 nm (380-420 nm) have proven effective for the inactivation of bacterial pathogens.

As one example, the device may be assembled similarly to a “blue-phosphor” LED device. A blue-phosphor LED device is a single package electronic device capable of emitting light. The embodiment of the device depicted in FIG. 2, as well as several of the other figures, for example, could be architecturally similar to a “blue-phosphor” LED device. Typically, in a “blue-phosphor” LED device, a semiconductor LED capable of emitting blue light is covered or surrounded by a phosphor material or otherwise placed so that light emitted from the diode passes though the phosphor. The “blue-phosphor” LED device emits some portion of the original blue light from the LED, and some of the light from the phosphor which has been converted from blue light. The “blue-phosphor” LED device has a combined light emission ratio of the blue light and the light emitted from the phosphor to emit a light that is overall perceived as white.

In some embodiments of the disclosure, 10% or less blue light (440 nm-495 nm) is emitted within the entire emitted spectral energy of the light emitting devices of the disclosure. In some instances, below 7% blue light is emitted by the light emitting devices of the disclosure. This is a low value compared to a conventional blue pumped LED which typically contains 15-20% blue light emitted within the entire emitted spectral energy. Such low blue light content as emitted by the light emitting devices of the disclosure allows for minimal suppression of melatonin in humans which contributes to better sleep, improved behavior, and mood. Thus, the light emitting devices according to the disclosure can be used for circadian rhythm effects.

The LED device according to embodiments of the disclosure is assembled similarly to a “blue-phosphor” LED device but includes a semiconductor LED that emits a majority of light/peak of light within the 380-420 nm wavelength range rather than wavelengths within the conventional range of approximately 440-495 nm, which would be perceived as blue. Light in the 380-420 nm wavelength is capable of killing or deactivating microorganisms such as but not limited to Gram positive bacteria, Gram negative bacteria, bacterial endospores, mold and yeast and filamentous fungi. Some Gram positive bacteria that can be killed or deactivated include Staphylococcus aureus (incl. MRSA), Clostridium perfringens, Clostridium difficile, Enterococcus faecalis, Staphylococcus epidermidis, Staphyloccocus hyicus, Streptococcus pyogenes, Listeria monocytogenes, Bacillus cereus, Mycobacterium terrae, Lactococcus lactis, Lactobacillus plantarum, Bacillus circulans and Streptococcus thermophilus. Some Gram negative bacteria include Acinetobacter baumannii, Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus vulgaris, Escherichia coli, Salmonella enteritidis, Shigella sonnei, Serratia spp. and Salmonella typhimurium. Some bacterial endospores include Bacillus cereus and Clostridium difficile. Some yeast and filamentous fungi include Aspergillus niger, Candida albicans, and Saccharomyces cerevisiae. Light in the 380-420 nm wavelength has been effective against every type of bacteria tested, although it takes different amounts of time or dosages dependent on species. Based on known results it is expected to be effective against all gram-negative and gram-positive bacteria to some extent over a period of time. It can also be effective against many varieties of fungi, although these will take longer to show an effect.

To kill or deactivate microorganisms on a target surface, a certain intensity of light from a lighting device/fixture is typically required. In some embodiments of the disclosure, a light emitting device emitting light with an intensity of at least 0.01 mW/cm² (in the 380-420 nm range) on the target surface is attained.

The LED, according to embodiments of the disclosure, or the light emitter(s), according to other embodiments of the disclosure, are surrounded by a phosphor material capable of absorbing and converting some portion of that anti-microbial light emitted from the LED or light emitter(s) (380-420 nm) to an alternative wavelength or wavelengths. This LED or other light emitter(s)-containing device can have a combination of selected phosphors, such as but not limited to Lutetium Aluminum Garnet and Nitride, that when combined at the proper ratios can emit a light perceived as white or a hue of white. This example LED or other light emitter(s)-containing device can have a CRI equal to or greater than 70. In some embodiments, this example LED device can have a CRI equal to or greater than 80. A percentage of spectral content of light emitted from the example LED device with approximately 380-420 nm wavelength can be equal to or greater than 10%. In some embodiments, light with wavelengths in the range from approximately 380-420 nm may comprise at least approximately 20%, 25%, 30%, 35%, 40%, 45%, or 50% of the total combined light emitted from the example LED device.

In some embodiments, the light-emitting device can be a surface mount LED device, which includes an LED and a light-conversion material. The surface mount LED device can be mounted onto a printed circuit board (“PCB”) or otherwise configured to be capable of transferring power to the light-emitting device and to the LED. The LED can be coupled to the PCB through bond wires or leads which enable an electrical connection from the LED to the outside of the device. The device may have a lens, encapsulant, or other protective cover. The embodiments shown in FIGS. 1-8 and FIGS. 17-20 can be embodied as surface mount LED devices by arranging them with wires or leads connected to the respective LEDs and configured to be connected to a PCB.

In additional embodiments, the light-emitting device can be a through-hole LED device, which is similar to a surface mount package but is intended to be mounted to a PCB board or otherwise configured to be capable of transferring power into the device and the light emitter via conductive legs which mate with matched holes or vias on the PCB or similar structure. The legs are coupled to the PCB or similar structure through solder or another conductive medium.

In some embodiments, the light-emitting device can be a chip-on-board LED arrangement, which is a package with one or more light sources and a light converting-material. The one or more light sources can be mounted directly to a substrate, and the light-converting material can be placed so a desired portion of emitted light is converted by the light converting material.

In another embodiment, the light-emitting device can be a chip scale package (CSP) or a flip chip CSP, both of which packages the emitters without using a traditional ceramic/plastic package and/or bond wires, allowing the substrate to be attached directly to the printed circuit board.

Unlike previous attempts with devices to produce acceptable light spectrums, which required multiple different light emitters to be incorporated into a device to achieve white light of acceptable characteristics, embodiments of the disclosure do not require multiple different light emitters, which would each require its emitted light to be combined through optics or housing structures, which in turn would require increased electronics, controls, optics, and housing structures. The additional features and increased cost metrics associated with multiple-light-emitter light-emitting devices make color mixing methods inherently cumbersome for these light-emitting devices as compared to light-emitting devices with single light emitters, which can produce a combined light spectrum out of a single assembly.

As mentioned above, typical multiple light emitter devices require the emitted light to be combined/mixed in an optical chamber (by way of, e.g., optics or housing structures). While some embodiments of the disclosure do not require multiple different emitters (i.e., one/single light emitter devices), other embodiments of the disclosure can include multiple-light-emitter light-emitting devices and such multiple light emitter devices of the disclosure do not combine/mix the emitted light in an optical chamber. Multiple light emitter devices of the disclosure are configured such that the emitted light is combined/mixed before it exits a given LED package and thus does not require combining/mixing in the optical chamber.

In one embodiment, a device is disclosed which comprises a unit that uses only violet LEDs (approximately 405 nm) to create white light (see e.g., FIG. 17 through FIG. 20), while maintaining the disinfection capabilities of the desired spectrum. Color temperatures of 2700 k, 3500 k, and 4100 k, with CRI above 80 are possible with a single light emitter (e.g., LED) according to embodiments of the disclosure. Generally, a CCT range of 2700-5000 k with minimum CRI of 70, and violet spectral content above 10% is possible. In some embodiments, the use of two or more light-converting materials can achieve these values. In some embodiments, phosphors that convert light to each of red (620-750 nm), green (495-570 nm), and blue (440-495 nm) wavelengths can be used, such as Nitride, Lutetium Aluminum Garnet, and Ca₂PO₄C1:Eu²⁺, respectively.

A difficult aspect to overcome is a lack of blue light emission in contrast to conventional LED white lights. While violet light can be combined with other colors to create white, it has been found that differences in perception from person to person exist for violet light. This means different people see a combined light differently; some might see too much violet, while others might see not enough violet; causing a misrepresentation of the color of white light overall. In addition, without enough blue light it is more difficult to achieve a high CRI. Previous attempts have utilized blue LEDs mixed with the other colors to boost CRI and balance the color of the mixed light output. Even with this approach some people still see the light differently depending on their sensitivity, but it has shown reduced differentiation of observed color overall of combined spectrums. Some embodiments herein instead add blue light through the use of phosphors, optical brighteners, or other blue emitting materials. These materials can absorb violet light and emit blue light, without the use of a discrete blue LED.

Some phosphor material compositions include aluminate phosphors (e.g., calcium aluminate, strontium aluminate, yttrium aluminate), silicate phosphors, garnet phosphors, nitride phosphors, oxynitride phosphors, Calcium Sulfide, Ca₂PO₄C1:Eu²⁺, LSN (La₃Si₆N₁₁:Ce³⁺), LYSN ((La,Y)₃Si₆N₁₁:Ce³⁺), CASN (CaAlSiN₃:Eu²⁺), SCASN ((Sr,Ca)AlSiN₃:Eu²⁺), KSF (K₂SiF₆:Mn⁴⁺), CSO (CaSc₂O₄:Ce³⁺), β-SiAlON ((Si,Al)₃(O,N)₄:Eu²⁺), Yttrium Aluminum Garnet (YAG:Y₃(Al,Ga)₅O₁₂:Ce³⁺), Lutetium Aluminum Garnet (LuAG: Lu₃Al₅O₁₂:Ce³⁺) and SBCA ((Sr,Ba)₁₀(PO₄)₆C₁₂:Eu²⁺). Some optical brightening agents are chemical derivatives of stilbene, coumarin, 1, 3 diphenyl pyrazoline, naphthalene dicarboxylic acid, heterocyclic dicarboxylic acid, and cinnamic acid. Additional light converting materials for use with OLEDs include, for example, phosphorescent materials, fluorophores, fluorescent dyes, conductive polymers, and organometallic phosphors.

FIGS. 16 and 21 serve as examples of color coordinates and ranges of color coordinates that could be achieved in practice in some embodiments of the disclosure. It should be understood that these are examples of some existing standards of color coordinates that can be achieved; other standards that exist or may be developed in the future for white light may be used. Additionally, the disclosed device may be approximately matched in color coordinates to CIE standard illuminants and/or standard illuminant families; it should be noted that the disclosed device may not match all defined characteristics of a standard illuminant, but in some embodiments will approximately match the x,y color coordinates. Some of these additional CIE standard illuminants include but are not limited to A, B, C, D50, D55, D65, D75, E, F1, F2, F3, F4, F5, F6, F7, F8, F9, F10, F11, and F12.

In another aspect of the disclosure, a light emitting device of the disclosure which contains at least two light emitters, each with their own light-converting material, can be configured such that the light emitted from a first light emitter (e.g., a first semiconductor die) and through a first light-converting material (e.g., a first phosphor) ultimately emits at one color temperature (e.g., 2200K) and the light emitted from a second light emitter (e.g., a second semiconductor die) and through a second light-converting material (e.g., a second phosphor) ultimately emits at another color temperature (e.g., 6500K). In such an example device, the amount of power provided to each light emitter (e.g., each semiconductor die within one single LED package) can vary independently of each other. This allows the white light emitting device, in one embodiment, to be color temperature tunable. In the case of the example, tunable between 2200K (warm) and 6500K (cool).

The foregoing description of various aspects of the disclosure has been presented for the purpose of illustration and description. It is not intended to be exhaustive or to limit the disclosure to the precise form disclosed, and obviously, many modifications and variations are possible. Such variations and modifications that may be apparent to one skilled in the art are intended to be included within the scope of the present disclosure as defined by the accompanying claims.

Claims

1. A method for inactivating microorganisms on a surface, the method comprising: emitting, with a first light source, a first light comprising a first correlated color temperature (CCT);emitting, with a second light source, a second light comprising a second CCT; andvarying respective power levels of the first light source and the second light source such that the first light and the second light combine to form white light comprising: an intensity associated with light in a 380-420 nanometer (nm) wavelength range sufficient to initiate inactivation of microorganisms on the surface; anda third CCT between the first CCT and the second CCT.

2. The method of claim 1, wherein the first CCT is 2200 kelvins (K) and the second CCT is 6500 K.

3. The method of claim 1, wherein the white light comprises a color rendering index (CRI) value within a range of 55 to 100.

4. The method of claim 1, wherein the white light has a color fidelity (Rf) value within a range of 60 to 100 and a color gamut (Rg) value within a range of 60 to 140.

5. The method of claim 1, wherein the light in the 380-420 nm wavelength range comprises at least 10% of a spectrum of the white light.

6. The method of claim 1, wherein the white light has a proportion of spectral energy measured in a 440 nm to 495 nm wavelength range of 10% or less.

7. The method of claim 1, wherein the intensity is at least 0.01 milliwatts per centimeter squared (mW/cm2).

8. A method for inactivating microorganisms on a surface, the method comprising: emitting, with a first light source at a first power level at a first time, a first light at a first correlated color temperature (CCT);emitting, with a second light source at a second power level at the first time, a second light at a second CCT;emitting, with the first light source at a third power level at a second time, the first light;emitting, with the second light source at a fourth power level at the second time, the second light;wherein the first light and the second light combine at the first time to form a first white light comprising a third CCT between the first CCT and the second CCT;wherein the first light and the second light combine at the second time to form a second white light comprising a fourth CCT between the first CCT and the second CCT; andwherein each of the first white light and the second white light comprises an intensity associated with light in a 380-420 nanometer (nm) wavelength range sufficient to initiate inactivation of microorganisms on the surface.

9. The method of claim 8, wherein the first CCT is 2200 kelvins (K) and the second CCT is 6500 K.

10. The method of claim 8, wherein the first white light or the second white light comprises a color rendering index (CRI) value within a range of 55 to 100.

11. The method of claim 8, wherein the first white light or the second white light comprises a color fidelity (Rf) value within a range of 60 to 100 and a color gamut (Rg) value within a range of 60 to 140.

12. The method of claim 8, wherein the light in the 380-420 nm wavelength range comprises at least 10% of a spectrum of the first white light or the second white light.

13. The method of claim 8, wherein the first white light or the second white light comprises a proportion of spectral energy measured in a 440 nm to 495 nm wavelength range of 10% or less.

14. The method of claim 8, wherein the intensity is at least 0.01 milliwatts per centimeter squared (mW/cm2).

15. The method of claim 8, further comprising: converting at least a portion of the first light from a first wavelength to a second wavelength different from the first wavelength; andconverting at least a portion of the second light from the first wavelength to a third wavelength different from the first wavelength.

16. A method for inactivating microorganisms on a surface, the method comprising: emitting, via at least two light emitters, first light comprising a first wavelength in a range of 380-420 nanometers (nm) and comprising an intensity sufficient to initiate inactivation of microorganisms on the surface;converting, via a first light-converting material arranged in a direct path of a first light emitter of the at least two light emitters, a portion of the first light from the first wavelength to a second wavelength;converting, via a second light-converting material arranged in a direct path of a second light emitter of the at least two light emitters, a portion of the first light from the first wavelength to a third wavelength, such that the first wavelength, the second wavelength, and the third wavelength combine to form white light; andtuning, based on independently varying power levels of the at least two light emitters, the white light from a first CCT to a second CCT.

17. The method of claim 16, further comprising varying, based on the tuning, a proportion of spectral energy in the range of 380-420 nm.

18. The method of claim 16, further comprising varying, based on the tuning, a proportion of spectral energy in a range of 440-495 nm.

19. The method of claim 16, wherein the first CCT is 2200 kelvins (K) and the second CCT is 6500 K.

20. The method of claim 16, wherein the tuning further comprises tuning the white light between a first color rendering index (CRI) of 55 to a second CRI of 100.