Full-spectrum white light-emitting device

Abstract

The present disclosure provides a full-spectrum white light-emitting device, which includes: a photoluminescent material for generating light having a peak emission wavelength ranging from 490 nm to 680 nm; and a broadband solid-state excitation source for generating broadband excitation light having a main wavelength ranging from 420 nm to 480 nm. The device generates white light having a spectrum, the intensity of which decreases from its maximum value in the orange to red wavelength region of the spectrum to about 50% of the maximum value at wavelengths ranging from 645 nm to 695 nm, and within the wavelength range from about 430 nm to about 520 nm, the maximum percentage intensity deviation of the white light from the intensity of the light of the blackbody curve or CIE standard illuminant D is less than 60%.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 62 / 872,277, filed Jul. 9, 2019, and U.S. Utility Patent Application No. 16 / 517,524, filed Jul. 19, 2019, the entire disclosures of which are hereby incorporated by reference. Field of the Invention

[0003] Embodiments of the present invention relate to all-solid-state spectral white light-emitting devices including photoluminescent wavelength conversion materials. More specifically, but not exclusively, embodiments relate to all-spectrum white light-emitting devices for generating all-spectrum white light that closely resembles natural daylight and has a spectrum from blue to red. Background of the Invention

[0004] White light-emitting LEDs (“white LEDs”) include one or more photoluminescent materials (typically inorganic phosphor materials) that absorb a portion of the blue light emitted by the LED (solid-state excitation source) and re-emit visible light of a different color (wavelength). The combination of the portion of the blue light generated by the LED that is not absorbed by the phosphor material and the light emitted by the phosphor provides light that appears white to the eye. Due to their long expected operating life (>50,000 hours) and high efficiency (100 lumens per watt and higher), white LEDs have rapidly replaced conventional fluorescent lamps, compact fluorescent lamps, and incandescent lamps.

[0005] There are various metrics for quantifying the characteristics and quality of light generated by white lighting sources. Two of the most commonly used metrics within the solid-state lighting industry are the correlated color temperature (CCT) and the International Commission on Illumination (CIE) general color rendering index (CRI) Ra.

[0006] The CCT of a lighting source is measured in Kelvin (K) and is the color temperature of a Planck (blackbody) radiator that emits light corresponding to the color of the light generated by the lighting source.

[0007] The general CRI Ra characterizes the faithfulness with which a lighting source presents the true colors of objects and is a measure of the adequacy of the comparison of the lighting of the light source to that provided by a reference source for eight color test samples (R1 to R8). Generally, the higher the value, the closer it indicates to a blackbody radiator and natural daylight. The general CRI Ra can take negative values and has a maximum value of 100. Since color samples R1 to R8 are all pastel colors (low-saturation colors from "light grayish red" to "red-violet"), the general CRI Ra gives a useful measure of the nuances in the light output of incandescent light sources that produce a full spectrum approaching that of daylight. However, for white LEDs whose spectra consist of peaks, the general CRI Ra proves to be insufficient as it is an average measure of color rendering within a limited color range and does not give information about the performance of the lighting source for specific colors or highly saturated colors. Therefore, when characterizing full-spectrum solid-state white light-emitting devices, CRI color samples R9 to R12 (saturated colors "saturated red", "saturated yellow", "saturated green", "saturated blue") and R13 to R15 ("light skin color", "leaf green", "medium skin color") should be considered to give a meaningful characterization of full-spectrum light.

[0008] Good lighting design is inherently human-centered because lighting can affect the human sleep cycle, circadian rhythm, alertness, and other non-visual responses. The safety of LED (solid-state) lighting for human health has been the subject of recent scrutiny. There is growing concern that artificial light disrupts the normal regulation of human physiology and psychology, such as hormone synthesis, sleep-wake cycles, and alertness levels. Specifically, recent evidence indicates that high color temperature (5000K) and high illuminance light (such as that produced by LEDs, for example) suppress pre-sleep melatonin secretion and reduce subjective alertness. It has also been reported that blue light is more likely than other colors to affect an organism by disrupting its biological processes, which depend on the natural cycle of day and night (circadian rhythm). It is believed that exposure to blue light late at night and at night may be harmful to health.

[0009] Various metrics have been proposed for predicting the melatonin suppression effect. Two of the more common metrics for measuring circadian stimulation are (i) the circadian action factor (CAF) and (ii) the melanopsin response (MR). The CAF and MR are the ratios of the radiometric circadian luminous efficacy (CER) to the radiometric luminous efficacy (LER) and each provides a measure of the brain's sensitivity to light; that is, a measure of the non-visual sensitivity of humans to light. The CAF is based on studies that measure human melatonin levels before and after exposure to light of a specific wavelength to establish the circadian action spectrum (CAS) or the circadian sensitivity spectrum c(λ). The CAF (denoted as a cv) is the ratio of the radiometric circadian efficacy to the photopic efficacy. The MR is based on the absorption spectrum of the melanopsin photopigment found in mammalian ipRGCs (intrinsically photosensitive retinal ganglion cells) to establish the melanopsin response (sensitivity) spectrum m(λ). The MR is the ratio of the radiometric circadian efficacy to the photopic efficacy. Recently, a new metric, the equivalent melanopic lux (EML), weighted to the spectral response of ipRGCs has been proposed.

[0010] A further potential problem with LED lighting is photochemical retinopathy, i.e., the possibility of photochemical damage to the retina, which can be caused by overexposure to violet to blue light. This is known as blue light hazard (BLH) and is similar to CAF and MR in that it has a corresponding blue sensitivity spectrum b(λ). The risk of BLH is sometimes associated with LEDs, even though white-emitting LEDs do not contain significantly more blue light than other types of sources at the same color temperature. That is, for high CCT (≥5000K) white LEDs, BLH is a potential eye health problem because the blue peak generated by the LEDs is extremely high in the CAF and MR wavelength regions of the spectrum. According to current international standards, sources that emit white light and are used in general lighting applications are not considered harmful to the retinas of healthy adults. That is, the optical safety of specialty lamps or colored light sources must be considered on a case-by-case basis, and additional evaluation is required for light sources used around susceptible populations (e.g., infants or adults with certain types of eye diseases).

[0011] Currently, in the LED lighting industry, full-spectrum LED devices seek to produce white light with a general CRI Ra equal to 100, as exhibited by incandescent lamps and blackbody radiation. However, it has been found that such LEDs sacrifice efficacy by 15% to 30% compared to white LEDs that produce light with a CRI Ra of approximately 80 (CRI80).

[0012] The present invention is directed to at least partially overcoming the disadvantages of known solid-state white light-emitting devices and providing a human-centered full-spectrum white light-emitting device having an efficacy that is at least close to or exceeds that of current CRI80 devices. Summary of the Invention

[0013] The present invention relates to a full-spectrum white light-emitting device for generating full-spectrum white light that is as close as possible to natural daylight and has spectral content from blue wavelengths to red wavelengths.

[0014] Specifically, although not exclusively, at least some embodiments of the present invention relate to white light emitting devices for generating white light that is close to natural light in the blue to cyan wavelength region of the spectrum. According to an embodiment of the present invention, such white light emitting devices generate full-spectrum white light that is close to natural light in the blue to cyan wavelength region (430 nm to 520 nm), where human non-visual perception measured by the circadian action factor (CAF) and the melanopsin response (MR) is most affected. It is believed that white light having this spectral characteristic is beneficial to human well-being because this part of the wavelength spectrum affects melatonin secretion, which may affect the circadian rhythm cycle. The full-spectrum white light emitting device according to the present invention utilizes a broadband solid-state excitation source, such as a blue LED, which generates broadband excitation light having a peak wavelength from about 420 nm to about 480 nm (i.e., in the blue wavelength region of the visible spectrum). In this patent specification, "broadband" is used to denote light having a full width at half maximum (FWHM) of at least 25 nm. For example, the FWHM can be at least 30 nm or at least 50 nm and can have an FWHM ranging from about 25 nm to about 70 nm; optionally it can have an FWHM in the range from about 30 nm to about 70 nm. Broadband can also be used to denote blue light composed of a combination of at least two different wavelength blue light emissions in the wavelength range from about 420 nm to about 480 nm. The use of broadband blue excitation light enables the light emitting device to generate full-spectrum light that is close to natural light in the blue to cyan wavelength region (430 nm to 520 nm) of the spectrum.

[0015] Embodiments of the present invention further relate to full-spectrum white light emitting devices for generating white light having an optimized (reduced) light intensity at wavelengths corresponding to the red wavelength region of the spectrum to improve efficiency. In an embodiment, the device includes an orange to red photoluminescent material, the peak emission wavelength / FWHM of which is selected to reduce the light intensity (photon count) at wavelengths corresponding to the red wavelength region (range) of the spectrum, specifically to reduce the light intensity of wavelengths longer than about 650 nm, which may affect the values of CRI R9 ("saturated red") and CRI R8 ("red-violet"), at which the photopic response of the eye (i.e., the photopic luminosity function) is typically low (about 0.1).

[0016] According to one aspect of the present invention, a full-spectrum white light-emitting device is contemplated, which comprises: a photoluminescent material for generating light having a peak emission wavelength ranging from about 490 nm to about 680 nm; and a broadband solid-state excitation source for generating broadband excitation light having a main wavelength ranging from about 420 nm to about 480 nm, wherein the device generates white light having a certain spectrum, the intensity of which decreases from its maximum value in the orange-to-red wavelength region of the spectrum to about 50% of the maximum value at wavelengths ranging from about 645 nm to about 695 nm, and wherein in the wavelength range from about 430 nm to about 520 nm, the maximum percentage intensity deviation of the white light from the intensity of the blackbody curve or the light of CIE standard illuminant D of the same correlated color temperature is less than 60%. More specifically, the maximum intensity in the orange-to-red region of the spectrum corresponds to the light generated by photoluminescence conversion and the maximum intensity occurs at a wavelength longer than about 570 nm. For example, the maximum intensity may occur at a wavelength within the range from about 590 nm to about 620 nm.

[0017] The case may be that at least one of the maximum percentage intensity deviations of the light emitted by the device is less than 50%, 40%, 30%, 20%, and 10%.

[0018] The white light may have a CAF within 5% of the circadian action factor (CAF) of the blackbody curve or CIE standard illuminant D.

[0019] In an embodiment, the white light generated by the device has a CRI R9 less than 90 and / or a CRI R8.

[0020] The case may be that the white light has a certain spectrum and has a CRI Ra of at least 80, and the intensity of the spectrum decreases from its maximum value in the orange-to-red wavelength region to about 50% of the maximum value at wavelengths ranging from about 645 nm to about 665 nm.

[0021] The white light may have a certain spectrum and have a CRI Ra of at least 90 and a CRI R9 greater than 50, and the intensity of the spectrum decreases from the maximum value of the light emitted by the device to about 50% of the maximum value at wavelengths ranging from about 665 nm to about 690 nm.

[0022] In an embodiment, the white light may have a certain spectrum and have a CRI Ra of at least 95 and a CRI R9 greater than 60, and the intensity of the spectrum decreases from the maximum value of the light emitted by the device to about 50% of the maximum value at wavelengths ranging from about 680 nm to about 695 nm.

[0023] The case may be that the photoluminescent material includes at least one or a combination of photoluminescent materials that produce light having a peak emission wavelength from about 620 nm to about 655 nm.

[0024] The white light may have a correlated color temperature from about 2700 K to about 3000 K and the device may have an efficacy of at least 102 lm / W.

[0025] In an embodiment, the white light may have a correlated color temperature from about 4000 K to about 6800 K and the device may have an efficacy of at least 110 lm / W.

[0026] The case may be that the broadband solid-state excitation source generates broadband excitation light having an FWHM of at least 25 nm.

[0027] The broadband excitation light may include a combination of blue light emissions of two or more different wavelengths. The blue light emissions of different wavelengths can be produced in two ways: (i) using multiple individual blue LEDs (narrowband LEDs) with different peak wavelengths or (ii) using an individual LED (broadband LED) with multiple different quantum wells, such as specially designed multiple different quantum wells in the active region, to produce multiple blue wavelength emissions. Thus, the broadband solid-state excitation source can be composed of one or more narrowband solid-state light sources; for example, an LED or a laser diode, each of which "directly" produces narrowband blue light with different peak wavelengths from 420 nm to 480 nm. In some embodiments, there is a wavelength difference of at least 5 nm between at least two blue light emissions, or there is a wavelength difference of at least 10 nm between at least two blue light emissions.

[0028] In an embodiment, the broadband solid-state excitation source may include: a first solid-state light source for producing a blue light emission having a first peak wavelength from 420 nm to 480 nm; and a second solid-state light source for producing a different blue light emission having a second peak wavelength from 420 nm to 480 nm. The first peak wavelength may be from 420 nm to 450 nm; and the second peak wavelength may be from 450 nm to 480 nm. The broadband blue excitation source may further include a third solid-state light source for producing a blue light emission having a third peak wavelength from 420 nm to 480 nm, the third peak wavelength being different from the first and second peak wavelengths.

[0029] Alternatively, the broadband solid-state excitation source also encompasses broadband solid-state light sources; for example, broadband blue LEDs, such as InGaN / GaN blue LEDs having an active region that uses different quantum wells in a multiple quantum well (MQW) structure to directly produce multiple different wavelength blue light emissions. In some embodiments, the broadband solid-state excitation source includes an LED having at least two different quantum wells, each of which produces a blue light emission having a corresponding different peak wavelength.

[0030] The broadband solid-state excitation source of the present invention is to be contrasted with known white LEDs that utilize narrow-band blue LEDs that produce blue light having a single narrow-band wavelength with a FWHM in the range of 15 nm to 20 nm. The broadband blue solid-state excitation source of the present invention is to be further contrasted with known white LEDs that utilize UV solid-state light sources (UV LEDs), where the blue excitation light is indirectly generated through a photoluminescence conversion process of UV light using a blue-emitting (420 nm to 480 nm) photoluminescent material (phosphor). In other words, the broadband solid-state excitation source / white light-emitting device according to the present invention does not utilize / contain a photoluminescent material to produce excitation light in the range of 420 nm to 480 nm.

[0031] In an embodiment, the photoluminescent material may include: a first photoluminescent material having a peak emission wavelength from 490 nm to 550 nm; and a second photoluminescent material having a peak emission wavelength from 600 nm to 680 nm.

[0032] According to one aspect, the present invention encompasses a full-spectrum white light-emitting device that includes: a photoluminescent material for producing light having a peak emission wavelength from about 490 nm to about 680 nm; and a broadband solid-state excitation source for producing broadband excitation light having a main wavelength from about 420 nm to about 480 nm, where the device produces white light having a correlated color temperature from about 1800 K to about 6800 K and where the white light has a certain spectrum that has a CAF within 5% of the CAF of the blackbody curve or CIE standard illuminant D at the same correlated color temperature.

[0033] In an embodiment, within the wavelength range from about 430 nm to about 520 nm, there may be a maximum percentage intensity deviation of the intensity of the white light from the light of the blackbody curve or CIE standard illuminant D at the same correlated color temperature.

[0034] The case may be that the maximum percentage intensity deviation of the light is less than at least one of 50%, 40%, 30%, 20%, and 10%.

[0035] The white light may have a certain spectrum, and the intensity of the spectrum drops to half of its maximum intensity at wavelengths from about 645 nm to about 695 nm.

[0036] In an embodiment, the white light may have a CRI R9 less than 90.

[0037] The situation can be that the white light has a correlated color temperature ranging from about 2700K to about 3000K and the device has an efficacy of at least 102 lm / W, or the white light has a correlated color temperature ranging from about 4000K to about 6800K and the device has an efficacy of at least 110 lm / W.

[0038] Embodiments of the present invention find utility in encapsulated white light emitting devices, where photoluminescent materials (such as yellow-to-green and orange-to-red photoluminescent materials) are encapsulated with a broadband solid state excitation source such as surface mount devices, chip-on-board, and filaments. In other embodiments, the photoluminescent materials can be located remotely from the broadband solid state excitation source. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] These and other aspects and features of the present invention will become apparent to those of ordinary skill in the art upon reading the following description of specific embodiments of the invention in conjunction with the accompanying drawings, in which:

[0040] Figure 1a and 1b shows a remote phosphor full-spectrum white light emitting device according to some embodiments;

[0041] Figure 2a is a schematic diagram of a broadband blue solid state excitation source in a full-spectrum white light emitting device for Figure 1a and 1b according to an embodiment of the present invention;

[0042] Figure 2b is a schematic diagram of a broadband blue solid state excitation source in a full-spectrum white light emitting device for Figure 1a and 1b according to another embodiment of the present invention;

[0043] Figure 3a is a schematic cross-sectional view of a full-spectrum white light emitting device according to some embodiments;

[0044] Figure 3b is a schematic cross-sectional view of a full-spectrum white light emitting device according to some embodiments;

[0045] Figure 4a and 4b is a schematic diagram of a full-spectrum white light emitting device according to some embodiments;

[0046] Figure 5Shown are: (A) intensity spectra, normalized intensity I versus wavelength (nm), of the following three: (i) a known full-spectrum luminescent device using a narrowband excitation source - the spectrum is represented as A (dotted line), (ii) a full-spectrum luminescent device according to the present invention using a broadband excitation source - the spectrum is represented as B (thin solid line), (iii) a blackbody curve (bbc) (dashed line) for a CCT nominally the same as the CCTs of spectra A and B; and (B) circadian action spectrum (CAS) - thick solid line, relative quantum sensitivity versus wavelength (nm);

[0047] Figure 6 Shown are intensity spectra, normalized intensity (normalized to CIE 1931 XYZ relative luminance Y = 100) versus wavelength (nm), of the following four: (i) Dev.1 (solid line), (ii) Dev.2 (thick dashed line), (iii) Com.l (dotted line), and (iv) Planck spectrum (thin dashed line) for a CCT of 2700K nominally the same as those of Dev.l, Dev.2, and Com.l;

[0048] Figure 7a Shown are intensity spectra, normalized intensity (normalized to CIE 1931 XYZ relative luminance Y = 100) versus wavelength (nm), of the following five: (i) Dev.3 (solid line), (ii) Dev.4 (thick dashed line), (iii) Dev.5 (dash-dotted line), (iv) Com.2 (dotted line), and (v) Planck spectrum (thin dashed line) for a CCT of 3000K nominally the same as those of Dev.3, Dev.4, Dev.5, and Com.2;

[0049] Figure 7b Shown are intensity spectra, normalized intensity (normalized to CIE 1931 XYZ relative luminance Y = 100) versus wavelength (nm), of the following three: (i) Dev.4 (solid line), (ii) Com.2 (dotted line), and (iii) Planck spectrum (dashed line) for a CCT of 3000K nominally the same as those of Dev.4 and Com.2;

[0050] Figure 7c Shown are intensity spectra, normalized intensity (normalized to CIE 1931 XYZ relative luminance Y = 100) versus wavelength (nm), of the following three: (i) Dev.5 (solid line), (ii) Com.3 (dotted line), and (iii) Planck spectrum (dashed line) for a CCT of 3000K nominally the same as those of Dev.5 and Com.3;

[0051] Figure 8Show the intensity spectra, normalized intensity (normalized to CIE 1931 XYZ relative luminance Y = 100) against wavelength (nm) for the following three: (i) Dev.6 (solid line), (ii) Com.4 (dotted line), and (iii) Planck spectrum (dashed line) for a CCT of 4000K that is nominally the same as Dev.6 and Com.4;

[0052] Figure 9a Show the intensity spectra, normalized intensity (normalized to CIE 1931 XYZ relative luminance Y = 100) against wavelength (nm) for the following three: (i) Dev.7 (solid line), (ii) Com.5 (dotted line), and (iii) Planck spectrum (dashed line) for a CCT of 5000K that is nominally the same as Dev.7 and Com.5;

[0053] Figure 9b Show the intensity spectra, normalized intensity (normalized to CIE 1931 XYZ relative luminance Y = 100) against wavelength (nm) for the following three: (i) Dev.8 (solid line), (ii) Com.6 (dotted line), and (iii) Planck spectrum (dashed line) for a CCT of 5000K that is nominally the same as Dev.8 and Com.6;

[0054] Figure 10 is a side view of an LED filament lamp according to some embodiments; and

[0055] Figure 11a and 11b is a schematic cross-sectional B-B side and partially cut-away plane view of an LED filament white light emitting device in a lamp for Figure 10 ; Detailed Description

[0056] Embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which are provided as illustrative examples of the present invention to enable those skilled in the art to practice the present invention. Obviously, the following figures and examples are not intended to limit the scope of the present invention to a single embodiment, but other embodiments are possible by virtue of the exchange of some or all of the described or illustrated elements. In addition, in cases where certain elements of the present invention may be implemented using known components in part or in whole, only those parts of such known components that are necessary for understanding the present invention will be described, and detailed descriptions of other parts of such known components will be omitted so as not to obscure the present invention. In this specification, embodiments showing a single component should not be considered restrictive; on the contrary, the present invention is intended to cover other embodiments including multiple identical components, and vice versa, unless expressly stated otherwise herein. Further, the applicant does not intend to give any term in the specification or claims an uncommon or special meaning unless so expressly set forth. Additionally, the present invention covers current and future known equivalents of known components mentioned herein by way of illustration.

[0057] Throughout this specification, like reference numerals following the figure numbers are used to denote like features.

[0058] Embodiments of the present invention relate to white light-emitting devices that include a broadband solid-state excitation source, such as one or more LEDs, which are operable to produce broadband blue excitation light having a peak wavelength ranging from 420 nm to 480 nm. In this patent specification, "broadband" is used to denote light having a full width at half maximum (FWHM) of at least 25 nm. For example, the FWHM can be at least 30 nm or at least 50 nm and can have an FWHM in the range from 25 nm to 70 nm; optionally it can have an FWHM in the range from 30 nm to 70 nm. Broadband can also be used to denote blue light composed of a combination of emissions of at least two different wavelength blue lights in the wavelength range from 420 nm to 480 nm. More specifically, but not exclusively, embodiments of the present invention relate to white light-emitting devices for generating full-spectrum white light that approximates natural light in the blue-to-cyan wavelength region (from about 430 nm to about 520 nm) of the visible spectrum.

[0059] Remote Phosphor Full - Spectrum White - Light Emitting Device

[0060] Figure 1a and 1b illustrates a remote phosphor solid-state full-spectrum white light-emitting device according to an embodiment of the present invention, wherein Figure 1a is a partial cross-sectional plan view and Figure 1bIt is a cross-sectional view through A-A. Device 110 is configured to produce full-spectrum white light with a CCT (correlated color temperature) ranging from 1800K to 6800K. The device can be used alone or as part of a downlight or other lighting arrangement. Device 110 includes a hollow cylinder 112 composed of a disc-shaped base 114, a hollow cylindrical wall portion 116, and a detachable annular top 118. To assist in heat dissipation, base 114 is preferably made of aluminum, aluminum alloy, or any material with high thermal conductivity. Base 114 can be attached to wall portion 116 by screws or bolts or by other fasteners or by means of an adhesive.

[0061] Device 110 further includes a plurality (five in the Figure 1a and 1b example) of broadband blue solid-state excitation sources 120 mounted in thermal communication with a circular MCPCB (metal core printed circuit board) 122. Each embodiment of broadband blue solid-state excitation source 120 is described in Figures 2a to 4b In order to maximize light emission, device 110 may further include light reflecting surfaces 124 and 126 that respectively cover the face of MCPCB 122 and the inner curved surface of cylindrical wall 116.

[0062] Device 110 further includes a photoluminescent wavelength conversion component 128 that is positioned remotely from excitation source 120 and is operable to absorb a portion of the excitation light generated by excitation source 120 and convert that portion into light of a different wavelength through a photoluminescent process. The emission product of device 110 includes the combined light generated by broadband blue excitation source 120 and the photoluminescent light generated by photoluminescent wavelength conversion component 128. The photoluminescent wavelength conversion component can be formed of a light-transmissive material (e.g., polycarbonate, acrylic material, silicone material, etc.) incorporating a mixture of yellow, red, and / or green phosphors. Additionally, in an embodiment, the photoluminescent wavelength conversion component can be formed of a light-transmissive substrate coated with (a) phosphor material. Wavelength conversion component 128 is positioned remotely from excitation source 120 and is spatially separated from the excitation source. In this patent specification, "remotely" and "remote" denote a spaced-apart or separated relationship. Generally, the wavelength conversion component and the excitation source are separated by air, while in other embodiments, they can be separated by a suitable light-transmissive medium, such as, for example, a light-transmissive silicone or epoxy resin material. Wavelength conversion component 128 is configured to completely cover the housing opening such that all light emitted by the lamp passes through wavelength conversion component 128. As shown, wavelength conversion component 128 can be removably mounted to the top of wall portion 116 using top 118, thereby enabling easy change of the lamp's components and emission color.

[0063] Figure 2aSchematic diagram of a broadband blue solid-state excitation source 220 according to an embodiment of the present invention. The broadband blue solid-state excitation source 220 is configured to generate broadband blue excitation light having a peak wavelength in the blue wavelength region of the visible spectrum, from 420 nm to 470 nm. In this embodiment, it also has a FWHM from 25 nm to 50 nm. According to an embodiment of the present invention, the broadband blue solid-state excitation source 220 may include a first solid-state light source 230 and a second solid-state light source 232, which are narrow-band blue LED chips (such as blue-light-emitting GaN-based LED chips) in this example. The first solid-state light source 230 generates blue light emission having a first peak wavelength λ d1 from 420 nm to 470 nm and the second solid-state light source 232 generates blue light emission having a second peak wavelength λ d2 from 420 nm to 470 nm. The first and second solid-state light sources are selected such that the peak wavelengths of the light generated by the sources are different (i.e., λ d1 is different from λ d2 ). The combination of the light from the first and second solid-state light sources 230 / 232 constitutes the broadband blue excitation light output 242 of the broadband blue solid-state excitation source 220 and has a peak wavelength from 420 nm to 470 nm and a FWHM from 25 nm to 50 nm. It will be understood that in other embodiments, the solid-state excitation source may include a single solid-state light source. In the present specification, a single solid-state light source is defined as one or more solid-state light sources, each of which generates light having the same (i.e., single / individual) peak wavelength and having a FWHM of at least 25 nm.

[0064] As Figure 2a indicated, the broadband blue solid-state excitation source 220 may include surface mount devices (SMDs), such as, for example, an SMD 2835 LED package, where the first and second solid-state light sources are flip-chip bonded to the top surface of a substrate 234. Electrical contacts 236, 238 may be provided on the bottom surface of the substrate 234 for operating the excitation source. The first and second solid-state light sources 230, 232 may be encapsulated with a light-transmissive optical encapsulant 240 (such as, for example, a silicone or epoxy resin material).

[0065] Figure 2bSchematic diagram of a broadband blue solid-state excitation source 220 according to an embodiment of the present invention. The solid-state excitation source 220 is configured to generate excitation light having a peak wavelength ranging from 420 nm to 470 nm, i.e., in the blue wavelength region of the visible spectrum. In this embodiment, it also has a FWHM ranging from 25 nm to 50 nm. According to an embodiment of the present invention, the solid-state excitation source 220 includes a broadband solid-state light source 241, which in this example is a single broadband LED, such as an InGaN / GaN blue LED having an active region with multiple quantum wells (MQWs), as disclosed by Tran C A et al. in "Growth of InGaN multiple-quantum-well blue light-emitting diodes on silicone by metal organic vapor phase epitaxy" in Applied Physics Letters 75, 1494 (1999). The broadband solid-state light source 241 generates broadband blue light including multiple overlapping blue light emissions having a peak wavelength ranging from 420 nm to 470 nm. Thus, a single solid-state light source 241 generates light having a single / detached peak wavelength and having a FWHM of at least 25 nm.

[0066] As Figure 2b indicated, the solid-state excitation source 220 may include a surface mount device (SMD), such as an SMD2835 LED package for example, wherein the solid-state light source is flip-chip bonded to the top surface of a substrate 234. Electrical contacts 236, 238 may be provided on the bottom surface of the substrate 234 for operating the excitation source. The solid-state light source 241 may be encapsulated with a light-transmitting optical encapsulant 240 (such as a silicone or epoxy resin material for example).

[0067] Encapsulated Full - Spectrum White - Light Emitting Device

[0068] Figure 3a Schematic cross-sectional representation of a packaged full-spectrum white light-emitting device 310a according to an embodiment of the present invention. The device 310a is configured to generate full-spectrum white light having a CCT (correlated color temperature) ranging from 1800 K to 6800 K.

[0069] According to an embodiment of the present invention, the device 310a includes a broadband blue solid-state excitation source constituted by first and second solid-state light sources 330, 332 (such as blue light-emitting GaN (gallium nitride)-based LED chips) housed in a package 344. In a similar / same manner as described above, the first solid-state light source 330 may generate a first peak wavelength λ ranging from 420 nm to 470 nm d1and the second solid-state light source 332 can generate second main wavelength λ with a range from 420 nm to 470 nm d2 of blue light emission. The main wavelength λ of the first solid-state light source d1 is different from the main wavelength λ of the second solid-state light source d2 . The package (which may include, for example, a surface mount device (SMD)), for example, the SMD 2835 LED package includes an upper portion 346 and a base portion 348. The upper body portion 346 defines a notch 350 configured to receive the solid-state light sources 330, 332. The package 344 may further include electrical connectors 352 and 354 on the outer surface of the base of the package 344. The electrical connectors 352, 354 may be electrically connected to the electrode contact pads 356, 358, and 360 on the bottom surface of the notch 350. Using an adhesive or solder, the solid-state light sources (LED chips) 330, 332 may be mounted to a thermal pad 362 positioned on the bottom surface of the notch 350. The electrode pads of the LED chips may be electrically connected to the corresponding electrode contact pads 356, 358, and 360 on the bottom surface of the package 344 using bonding wires 362. Alternatively, the LED chips may be flip-chip mounted in the package and electrically connected to the package. The notch 350 is filled with a light-transmissive optical encapsulant 364, typically an optically clear silicone, which is loaded with a mixture of photoluminescent materials such that the exposed surfaces of the LED chips 330, 332 are covered with the photoluminescent / silicone material mixture. To enhance the emission brightness of the device, the walls of the notch 350 may be inclined and have a light-reflective surface. Of course, it will be understood that in other embodiments, one or more solid-state light sources (LED chips 330, 332) each generate light having the same (i.e., single / individual) main wavelength and having an FWHM of at least 25 nm.

[0070] Figure 3b is another embodiment of the present invention. It is similar to Figure 3a , except that the first and second narrowband solid-state light sources are replaced by two broadband blue LEDs 341a / 341b having an active region with multiple quantum wells. Generally, the first and second broadband blue solid-state light sources 341a / 341b each generate broadband blue excitation light having the same main wavelength λ d .

[0071] Figure 4a and 4b illustrate an on-board chip (COB) packaged full-spectrum white light-emitting device 410 according to an embodiment of the present invention, where Figure 4a is a plan view and Figure 4b is a cross-sectional view taken through B-B. The device 410 may be configured to generate warm white light having a CCT (correlated color temperature) from 2500 K to 5000 K and a CRI (color rendering index) greater than 95.

[0072] Device 410 includes a plurality (twelve in the Figure 4a example) of broadband blue solid-state excitation sources 420 mounted to be in thermal communication with a square MCPCB 468, such as broadband blue light-emitting GaN (gallium nitride)-based LED flip-chip dies.

[0073] As Figure 4a indicated, the excitation sources 420 can be configured as a generally circular array. The solid-state excitation sources (broadband LED dies) 420 can each generate excitation light having a peak wavelength λ d ranging from 440 nm to 455 nm. In this embodiment, they have a FWHM (full width at half maximum) ranging from 25 nm to 50 nm. Electrical contacts 472, 474 can be provided on the top surface of the MCPCB 468 for operating the white light-emitting device 410. As shown, the broadband LED flip-chip dies 420 are encapsulated with a light-transmissive optical encapsulant 466 (such as, for example, a silicone or epoxy resin material), which is loaded with a mixture of photoluminescent materials such that the exposed surface of the LED die 420 is covered with the photoluminescent / silicone material mixture. As shown, the light-transmissive encapsulant / photoluminescent material mixture 466 can be housed within an annular wall 470. Of course, it will be understood that in other embodiments, Figure 4a and 4b the arrangement depicted can include solid-state excitation sources 420 composed of two or more LEDs rather than a single broadband InGaN / GaN blue LED having an active region with multiple quantum wells.

[0074] Green - to - Yellow Photoluminescent Material

[0075] In this patent specification, green-to-yellow photoluminescent materials refer to materials that produce peak emission wavelengths (λ pe ) in the green-to-yellow wavelength region of the visible spectrum, i.e., from ~490 nm to ~570 nm. Preferably, the green-to-yellow photoluminescent materials have broad emission characteristics and preferably have a FWHM (full width at half maximum) of ~100 nm or wider. The green-to-yellow photoluminescent materials can include any photoluminescent material, such as, for example, garnet-based inorganic phosphor materials, silicate phosphor materials, and oxynitride phosphor materials. Examples of suitable green-to-yellow phosphors are given in Table 1.

[0076] In some embodiments, the green-to-yellow photoluminescent material includes a general composition Y3(Al,Ga)5O 12: Cerium-activated yttrium aluminum garnet phosphors such as Ce(YAG), for example, the YAG series phosphors from Intematix Corporation in Fremont, California, USA, which have a peak emission wavelength from 527 nm to 543 nm and an FWHM of ~120 nm. In this patent specification, the symbol YAG# represents the phosphor type, i.e., a YAG-based phosphor, followed immediately by the peak emission wavelength (#) in nanometers. For example, YAG535 represents a YAG phosphor with a peak emission wavelength of 535 nm. The green to yellow photoluminescent materials may include the general composition (Y,Ba)3(Al,Ga)5O 12 : Cerium-activated yttrium aluminum garnet phosphors such as Ce(YAG), for example, the GNYAG series phosphors from Intematix Corporation in Fremont, California, USA. In some embodiments, the green photoluminescent materials may include the general composition Lu3Al5O 12 : Aluminates (LuAG) phosphors such as Ce(GAL). Examples of such phosphors include, for example, the GAL series phosphors from Intematix Corporation in Fremont, California, USA, which have a peak emission wavelength from 516 nm to 560 nm and an FWHM of ~120 nm. In this patent specification, the symbol GAL# represents the phosphor type (GAL), i.e., a LuAG-based phosphor, followed immediately by the peak emission wavelength in nanometers (#). For example, GAL520 represents a GAL phosphor with a peak emission wavelength of 520 nm.

[0077] Examples of green to yellow silicate phosphors include europium-activated orthosilicate phosphors of the general composition (Ba,Sr)2SiO4:Eu, for example, the G, EG, Y, and EY series phosphors from Intematix Corporation in Fremont, California, USA, which have a peak emission wavelength from 507 nm to 570 nm and an FWHM from ~70 nm to ~80 nm.

[0078] In some embodiments, the green to yellow phosphors may include green-emitting oxynitride phosphors, as taught in U.S. Patent US8,679,367, titled "Green-Emitting (Oxy)Nitride-Based Phosphors and Light Emitting Devices Using the Same," the entire text of which is hereby incorporated by reference. This green-emitting oxynitride (ON) phosphor may have the general composition Eu 2+ :M 2+ Si4AlO x N (7-2x / 3) where 0.1 ≤ x ≤ 1.0 and M 2+is one or more divalent metals selected from the group consisting of Mg, Ca, Sr, Ba, and Zn. In the present patent specification, the symbol ON# represents the phosphor type (oxynitride), followed immediately by the peak emission wavelength in nanometers (λ pe )(#). For example, ON495 represents a green oxynitride phosphor having a peak emission wavelength of 495 nm.

[0079]

[0080] Orange - to - Red Photoluminescent Material

[0081] The orange-to-red photoluminescent material can include any orange-to-red photoluminescent material, typically a phosphor, which can be excited by blue light and is operable to emit light having a peak emission wavelength λ pe ranging from about 600 nm to about 670 nm and can include, for example, europium-activated silicon nitride-based phosphors, a-SiAlON, IIA / IIB group selenium sulfide-based phosphors, or silicate-based phosphors. Examples of orange-to-red phosphors are given in Table 2.

[0082] In some embodiments, the europium-activated silicon nitride-based phosphor includes a calcium aluminum silicon nitride phosphor (CASN) of the general formula CaAlSiN3:Eu 2+ The CASN phosphor can be doped with other elements of the general formula (Sr,Ca)AlSiN3:Eu 2+ such as strontium (Sr). In the present patent specification, the symbol CASN# represents the phosphor type (CASN), followed immediately by the peak emission wavelength in nanometers (λ pe )(#). For example, CASN615 represents an orange-to-red CASN phosphor having a peak emission wavelength of 615 nm.

[0083] In one embodiment, the orange-to-red phosphor can include an orange-to-red light-emitting phosphor, as taught in U.S. Patent No. 8,597,545, titled "Red-Emitting Nitride-Based Calcium-Stabilized Phosphors," the entire text of which is incorporated herein by reference. This red-emitting phosphor includes the chemical formula M a Sr b Si c Al d N e Eu fA nitride-based composition represented by: M is Ca, and 0.1 ≤ a ≤ 0.4; 1.5 < b < 2.5; 4.0 ≤ c ≤ 5.0; 0.1 ≤ d ≤ 0.15; 7.5 < e < 8.5; and 0 < f < 0.1; where a + b + f > 2 + d / v and v is the valence of M.

[0084] Alternatively, the orange-to-red phosphor may include an orange-to-red light-emitting nitride-based phosphor, as taught in U.S. Patent No. 8,663,502, titled "Red-Emitting Nitride-Based Phosphors," the entire text of which is hereby incorporated by reference. This red-emitting phosphor includes a nitride-based composition represented by the chemical formula M (x / v) M'2Si 5-x Al x N8:RE, where: M is at least one monovalent, divalent, or trivalent metal having a valence v; M' is at least one of Mg, Ca, Sr, Ba, Zn; and RE is at least one of Eu, Ce, Tb, Pr, and Mn; where x satisfies 0.1 ≤ x < 0.4, and where the red-emitting phosphor has a general crystal structure of M'2Si 5-x Al x N8:RE, with Al replacing Si within the general crystal structure, and M being located substantially at interstitial sites within the general crystal structure. An example of such a phosphor is the XR610 red nitride phosphor from Intematix Corporation of Fremont, California, USA, which has a peak emission wavelength of 610 nm.

[0085] The orange-to-red phosphor may also include an IIA / IIB group selenium sulfide-based phosphor. A first example of an IIA / IIB group selenium sulfide-based phosphor material has the composition MSe 1-x S x :Eu, where M is at least one of Mg, Ca, Sr, Ba, and Zn and 0 < x < 1.0. A specific example of such a phosphor material is the CSS phosphor (CaSe 1-x S x:Eu). Details of the CSS phosphor are provided in co-pending U.S. Patent Application Publication No. US2017 / 0145309 filed on September 30, 2016, the entire text of which is hereby incorporated by reference. The CSS orange to red phosphors described in U.S. Patent Publication US2017 / 0145309 can be used in the present invention. The emission peak wavelength of the CSS phosphor can be tuned from 600nm to 650nm by changing the S / Se ratio in the composition and exhibits a narrow-band red light emission spectrum with a FWHM from ~48nm to ~60nm (longer peak emission wavelengths generally have larger FWHM values). In this patent specification, the symbol CSS# indicates that the phosphor type (CSS) is followed by the peak emission wavelength (#) in nanometers. For example, CSS615 represents a CSS phosphor with a peak emission wavelength of 615nm. To improve reliability, the CSS phosphor particles may be coated with one or more oxides, such as aluminum oxide (Al2O3), silicon oxide (SiO2), titanium oxide (TiO2), zinc oxide (ZnO), magnesium oxide (MgO), zirconium oxide (ZrO2), boron oxide (B2O3), or chromium oxide (CrO). Alternatively and / or in addition, the narrow-band red phosphor particles may be coated with one or more fluorides, such as calcium fluoride (CaF2), magnesium fluoride (MgF2), zinc fluoride (ZnF2), aluminum fluoride (AIF3), or titanium fluoride (TiF4). The coating may be a single layer or multiple layers having a combination of the aforementioned coatings. The combination coating may be a coating having an abrupt transition between the first and second materials, or may be a coating in which there is a gradual / smooth transition from the first material to the second material, thereby forming a zone with a mixed composition that varies throughout the thickness of the coating.

[0086] In some embodiments, the orange to red phosphor may include an orange-emitting silicate-based phosphor, such as taught in U.S. Pat. No. 7,655,156, entitled “Silicate-Based Orange Phosphors,” which is hereby incorporated in its entirety. This orange-emitting silicate-based phosphor may have a general composition (Sr 1-x M x ) y Eu z SiO5, of which 0 <x≤0.5、2.6≤y≤3.3、0.001≤z≤0.5且M是选自由Ba、Mg、Ca及Zn组成的群组的一或多种二价金属。在本专利说明书中,符号O#表示磷光体类型(橙色硅酸盐)紧接其后是以纳米为单位的峰发射波长(λ pe )(#). For example, O600 represents an orange silicate phosphor having a peak emission wavelength of 600 nm.

[0087]

[0088] 1800K to 6800K Full - Spectrum White - Light Emitting Device

[0089] As described above, embodiments of the present invention relate to a full-spectrum white light-emitting device that produces full-spectrum light that is close to being similar to natural light, specifically but not exclusively in the blue-to-cyan wavelength region (430 nm to 520 nm) of the visible spectrum, where human non-visual perception, as measured, for example, by CAF (circadian action factor), is most affected. According to other aspects, the present invention relates to improving the efficacy of a full-spectrum white light-emitting device while maintaining a spectrum close to that of natural light in wavelengths within the range from about 430 nm to about 520 nm. The inventors have found that the efficacy of a full-spectrum white light-emitting device can be improved by optimizing (reducing) the intensity (photon count) of light corresponding to wavelengths in the red region of the spectrum, specifically reducing the light intensity at wavelengths that affect the values of CRI R9, i.e., "saturated red", and CRI R8, i.e., "red-violet". This efficacy improvement can be achieved by including an orange-to-red photoluminescent material, the peak emission wavelength / FWHM of which is selected such that the device produces full-spectrum white light having a spectrum with an intensity roll-off (tail) in the orange-to-red wavelength region of the visible spectrum, the intensity roll-off decreasing (falling) to half of its maximum intensity at wavelengths from about 645 nm to about 695 nm.

[0090] Figure 5 Shows: (A) the intensity spectra, normalized intensity I versus wavelength (nm), of the following three: (i) a known full-spectrum light-emitting device using a narrowband excitation source - the spectrum is represented as A (dotted line), (ii) a full-spectrum light-emitting device according to the present invention using a broadband excitation source - the spectrum is represented as B (thin solid line), (iii) a blackbody curve (bbc) (dashed line) for a CCT nominally the same as the CCTs of spectra A and B; and (B) the circadian action spectrum (CAS) - thick solid line, relative quantum sensitivity versus wavelength (nm). The figure defines various parameters for use in the patent specification and illustrates the principles of the present invention.

[0091] Reference Figure 5 , the circadian action spectrum (CAS) (also known as the spectral circadian efficacy function c(λ)) represents the non-visual relative sensitivity of humans to light. The maximum sensitivity of c(λ) occurs at a wavelength of 460 nm. The CAS indicates that the 430 nm to 520 nm portion of the spectrum is the most effective wavelength for providing a circadian input to regulate melatonin secretion.

[0092] Visually comparing spectrum A with the blackbody curve (bbc), it will be noticed that spectrum A exhibits peak 580, corresponding to the excitation light generated by a narrowband excitation source, and the intensity of said spectrum A significantly deviates from the intensity of the bbc (i.e., the peak intensity is much higher than the intensity of the bbc at the same wavelength). In contrast, spectrum B exhibits two peaks 582, 584, corresponding to the excitation light generated by a broadband excitation source, and the intensity of said spectrum B only slightly deviates from the intensity of the bbc compared to spectrum A (i.e., the peak intensity is slightly higher than the bbc at the same wavelength). Further note should be taken that peak 580 appears at a wavelength of 455 nm, i.e., close to the maximum sensitivity of CAS at a wavelength of 460 nm. Additionally, note should be taken that spectrum A exhibits a valley (trough) 586, and the minimum intensity of said spectrum A significantly deviates from the minimum intensity of the bbc (i.e., the valley intensity is much lower than the bbc). In contrast, spectrum B exhibits a valley (trough) 588, and the minimum intensity of said spectrum B only slightly deviates from the minimum intensity of the bbc compared to spectrum A (i.e., the valley intensity is slightly lower than the bbc). As can be seen from the figure, the smaller deviation of the emission peaks 582 and 584 of spectrum B (compared to peak 584 of spectrum A) and the valley 588 of spectrum B (compared to valley 586 of spectrum A) from the bbc indicates that spectrum B is closer to resembling the bbc (Planck spectrum) in the wavelength range from 430 nm to 520 nm (blue to cyan). It will be further understood that spectrum B is closer to resembling natural light in this wavelength region, where human non-visual perception measured by CAF (circadian action factor) is most affected and this can be beneficial to human well-being.

[0093] An index for quantifying how closely a spectrum resembles the bbc is the maximum (maximum / largest) percentage intensity deviation (I maxdev ) of the intensity of the light of the bbc at the same correlated color temperature. That is, in the wavelength range from approximately 430 nm to 520 nm, I maxdev is the maximum (maximum / largest) percentage intensity difference between the intensity of the spectrum and the intensity of the bbc. The maximum deviation can be positive (e.g., where the spectrum intensity is greater than the peak of the bbc) or negative (e.g., where the spectrum intensity is less than the valley of the bbc). To make a meaningful comparison of spectra, each spectrum is normalized to have the same CIE 1931 XYZ relative luminance Y. The spectra are normalized using the photopic luminosity function y(λ) of a standard observer (sometimes referred to as the photopic or visual luminous efficiency function v(λ)), which takes into account the photopic (visual) response of the observer and is for the same correlated color temperature. Thus, I maxdev is the maximum (maximum / greatest) percentage intensity difference between the normalized intensity of the spectrum and the normalized intensity of the bbc in the wavelength range from approximately 430 nm to 520 nm. I maxdev is defined as:

[0094]

[0095] For example, referring to Figure 5 , for spectrum A, the maximum deviation of the spectrum from the bbc corresponds to peak 580 at wavelength λ maxdev = 455 nm. The intensity of the spectrum at λ maxdev is represented as 590 and the intensity of the bbc at λ maxdev is represented as 592. Thus, using the above calculations, in the wavelength range from approximately 430 nm to approximately 520 nm, spectrum A has a maximum percentage intensity deviation I maxdev of 95%, i.e., at the maximum percentage intensity deviation, the normalized intensity of spectrum A at wavelength λ maxdev is 195% of the normalized intensity of the bbc at the same wavelength. In contrast, spectrum B has a maximum percentage intensity deviation I maxdev of only 30% (corresponding to peak 582), i.e., the normalized intensity of spectrum A at wavelength λ maxdev is 130% of the normalized intensity of the bbc at this wavelength.

[0096] The roll-off wavelength λ RO is defined as the wavelength at which the normalized intensity (I) decreases from its maximum intensity (denoted as I max ) in the orange to red wavelength region of the spectrum to half of its maximum intensity (denoted as 1 / 2I max ). As described above, the maximum intensity I max of the spectrum in this wavelength region corresponds to the photoluminescence conversion light and the maximum intensity occurs at wavelengths longer than approximately 570 nm. For example, the maximum intensity may occur at wavelengths in the range from approximately 590 nm to approximately 620 nm.

[0097] Testing Method for Encapsulated White - Light Emitting Device

[0098] The encapsulated test method involves measuring the total light emission of an encapsulated white light emitting device ( Figure 3a ) in an integrating sphere.

[0099] The encapsulated full-spectrum white light emitting devices (Dev.#) according to the present invention each include a 2835 (2.8 mm × 3.5 mm) SMD package containing three 1133 (11 mil × 33 mil) LED chips with peak wavelengths λ d1 = 443 nm, λ d2 = 451 nm, and λ d3 = 457 nm.

[0100] In this specification, the following nomenclature is used to represent white light-emitting devices: Com.# represents a comparative light-emitting device, in which each excitation source includes one or more solid-state light sources of a single dominant wavelength and Dev.# represents a white light-emitting device according to an embodiment of the present invention, in which each excitation source includes two solid-state light sources of different dominant wavelengths.

[0101] Testing Data of 2700K Full - Spectrum White - Light Emitting Device

[0102] Tables 3, 4 and 5 tabulate measured optical test data for 2700K white light emitting devices Dev. 1, Dev. 2 and known CRI90 comparative device Com. 1 and illustrate the impact on the efficiency of reducing red spectral content while maintaining blue and cyan spectral content.

[0103] The light emitting devices Dev.1 and Dev.2 each include a light source having a main wavelength λ d1 =443nm,λ d2 =451nm and λ d3 =457nm. Dev.1 includes a combination of GAL520 and CASN650 phosphors and Dev.2 includes a combination of GAL520, GAL530, CASN625 and CASN650 phosphors. The combination of CASN625 and CASN650 produces a peak emission of about 628nm, where the wavelength depends on the relative proportions of CASN625 and CASN650. Comparative device Com.1 includes a known 2835 packaged white light emitting device utilizing a narrowband excitation source and having a nominal CRI Ra of 90.

[0104] Figure 6 Intensity spectra, normalized intensity (normalized to CIE 1931 XYZ relative brightness Y = 100) versus wavelength (nm) are shown for the following four items: (i) Dev.1 (solid line), (ii) Dev.2 (thick dashed line), (iii) Com.1 (dotted line), and (iv) Planck spectrum for a CCT of 2700K that is nominally the same as Dev.1, Dev.2, and Com.1 (thin dashed line). In order to make a meaningful comparison of the spectra, each spectrum has been normalized so that each spectrum has CIE 1931 XYZ relative brightness Y = 100. The data is normalized using the CIE 1931 photometric function y(λ) of a standard observer, which takes into account the photopic response of the observer. Figure 6 The Planck spectrum (curve) or blackbody curve in represents the spectrum for a given color temperature (CCT) equal to a general CRI Ra of 100. Therefore, in order for a white light-emitting device of a given color temperature to have the highest possible color rendering, its emission spectrum should match the blackbody spectrum of the same color temperature as closely as possible.

[0105] Reference Figure 6 It will be noted that, compared to the comparative device Com.1 (including a narrowband excitation source), the effect on the emission spectral energy content of the devices Dev.1 and Dev.2 according to the invention (including broadband excitation sources) is a significant reduction in the intensity of the blue emission peak 682 at approximately 430 nm and 440 nm, respectively. As can be seen from the said figure, the reduction of the blue emission peak 682 of the devices Dev.1 and Dev.2 (compared to the peak 680 of Com.1) results in an emission spectrum that is closer to the Planck spectrum (i.e., closer to natural daylight) in the wavelength range from 430 nm to 520 nm (blue to cyan). More specifically, spectral analysis indicates that in the wavelength range from 430 nm to 520 nm (blue to cyan), there is a maximum percentage normalized intensity deviation I of approximately 60% between the normalized intensity of the light emitted by the devices Dev.1 and Dev.2 and the normalized intensity of the light of the blackbody curve (bbc) of the same correlated color temperature (2700K). maxdev . That is, Dev.1 and Dev.2 each produce light with an intensity that is 160% of the intensity of the light of the bbc at the same wavelength. The maximum deviation of the normalized intensity occurs at wavelengths λ of approximately 430 nm and approximately 440 nm maxdev respectively. This is to be contrasted with the known comparative device Com.1, which utilizes a narrowband excitation light source that produces white light with a maximum percentage deviation I of the normalized intensity of approximately 80% at a wavelength λ maxdev that appears at approximately 450 nm maxdev .

[0106] It will be appreciated that the devices Dev.1 and Dev.2 thus produce white light that is closer to natural light in this wavelength region, where human non-visual perception, measured by the CAF (circadian action factor), is most affected and this may be beneficial to human well-being. It is believed that this change in the spectral energy content caused by the broadband blue excitation source, which at least partially fills the valleys in the cyan region of the spectrum and reduces the peak overshoot in the blue region, explains the excellent color rendering properties of the devices of the invention. As can be seen from Table 3, the devices Dev.1 and Dev.2 produce white light with a CAF within 1.9% and 0.8% of the CAF of natural light, respectively (for the bbc at CCT 2700K). In contrast, the comparative device Com.1 has a CAF within 3.8% of the CAF of natural light.

[0107] Turning to the intensity roll-off (tail) of the spectrum in the orange to red wavelength region of the spectrum (i.e., for wavelengths longer than approximately 570 nm). For Dev.l, the maximum peak intensity (I maxFor Dev.1, the maximum peak intensity (I RO Dev.1) is approximately 8.2 and this occurs at a wavelength of approximately 640 nm. The intensity (I) drops to half of this value (1 / 2I max Dev.1) at a wavelength (λ max Dev.1).

[0108] For Dev.2, the maximum peak intensity (I max Dev.2) is approximately 7.6 and this occurs at a wavelength of approximately 620 nm. The intensity (I) drops to half of this value (1 / 2I RO Dev.2) at a wavelength (λ max Dev.2).

[0109]

[0110]

[0111]

[0112]

[0113] Referring to Tables 3, 4, and 5, it should be noted that Device Dev.1 has an efficacy of 104 lm / W and produces white light with a CRI Ra greater than or equal to 95 (96.9), where each of CRI R1 to CRI R15 is 90 or higher (91.2 to 99.0). In contrast, Device Dev.2 has an efficacy of 119 lm / W and produces white light with a CRI Ra greater than or equal to 95 (95.8), where CRI R1 to CRI R7 and CRI R10 to CRI R15 are approximately 90 or higher (89.5 to 99.3), while CRI R8 (corresponding to "red-violet") is greater than 72 and less than 90 (86.6), and CRI R9 (corresponding to "saturated red") is greater than 50 and less than 90 (69.6). Additionally, it should be noted that while the quality of the light produced by Dev.2 is substantially the same as that of Dev.1, the efficacy increases by substantially approximately 15% (from 104 lm / W to 119 lm / W).

[0114] From Figure 6 and Table 3 it will be apparent that, compared to Dev.1, the increase in efficacy of Dev.2 is a direct result of the spectral roll-off of Dev.2 occurring at a shorter wavelength (675 nm) than that of Dev.1 (690 nm), which reduces the light intensity in the red wavelength region of the spectrum.

[0115] Testing Data of 3000K Full - Spectrum White - Light Emitting Device

[0116] ​​​​​​​​​​Tables 6, 7, and 8 tabulate the measured optical test data of 3000K white light-emitting devices Dev.3 to Dev.5 and known 3000K CRI90 and CRI80 comparative devices Com.2 and Com.3, respectively, and illustrate the impact on the efficacy of reducing the red spectral content while maintaining the blue and cyan spectral content.

[0117] Each of light-emitting devices Dev.3 to Dev.5 includes a 2835 package containing three LED chips with peak wavelengths λ d1 = 443 nm, λ d2 = 451 nm, and λ d3 = 457 nm. Dev.3 includes a combination of GAL520 and CASN650 phosphors, while devices Dev.4 and Dev.5 include a combination of GAL520, GAL530, CASN625, and CASN650 phosphors, where Dev.5 includes a greater relative portion of CASN625 to CASN650 than Dev.4 (the combination of CASN625 and CASN650 in Dev.4 produces a peak emission at approximately 625 nm and the combination in Dev.5 produces a peak emission at approximately 628 nm). Comparative device Com.2 includes a known 2835 package white light-emitting device using a narrowband excitation source and having a nominal CRI Ra of 90. Com.3 includes a known 2835 package white light-emitting device using a narrowband excitation source and having a nominal CRI Ra of 80.

[0118] Figure 7a Show the intensity spectra, normalized intensity (normalized to CIE 1931 XYZ relative luminance Y = 100) versus wavelength (nm) for the following five: (i) Dev.3 (solid line), (ii) Dev.4 (thick dashed line), (iii) Dev.5 (dash-dotted line), (iv) Com.2 (dotted line), and (v) the Planck spectrum or blackbody curve (thin dashed line) for a CCT of 3000K that is nominally the same as Dev.3, Dev.4, Dev.5, and Com.2. Figure 7b Is the emission spectra, normalized intensity (normalized to CIE 1931 XYZ relative luminance Y = 100) versus wavelength (nm) for the following three: (i) Dev.4 (solid line), (ii) Com.2 (dotted line), and (iii) the Planck spectrum (dashed line) for a CCT of 3000K that is nominally the same as Dev.4 and Com.2. Figure 7cThe emission spectra, normalized intensities (normalized to CIE 1931 XYZ relative luminance Y = 100) versus wavelength (nm) of the following three: (i) Dev.5 (solid line), (ii) Com.3 (dotted line), and (iii) Planck spectrum (dashed line) for a CCT of 3000K which is nominally the same as Dev.5 and Com.3. Spectral analysis indicates that in the wavelength range of 430 nm to 520 nm (blue to cyan), there are maximum percentage normalized intensity deviations I of approximately 40%, approximately 50%, and approximately 60% between the normalized intensities of the light emitted by devices Dev.3, Dev.4, and Dev.5 and the normalized intensities of the light of a blackbody curve of the same correlated color temperature (3000K). maxdev . This is to be contrasted with the known comparative devices Com.2 and Com.3, which utilize narrowband excitation light sources that produce white light with maximum percentage deviations I of approximately 70% and 100% respectively (at a wavelength of approximately 450 nm). Additionally, as can be seen from Table 6, devices Dev.3, Dev.4, and Dev.5 produce white light with a CAF within 3.4%, 4.1%, and 3.4% of the CAF of natural light (bbc for CCT 3000K). In contrast, the comparative devices Com.2 and Com.3 have a CAF only within 11.5% and 9.5% of the CAF of natural light respectively. maxdev (at a wavelength of approximately 450 nm). Additionally, as can be seen from Table 6, devices Dev.3, Dev.4, and Dev.5 produce white light with a CAF within 3.4%, 4.1%, and 3.4% of the CAF of natural light (bbc for CCT 3000K). In contrast, the comparative devices Com.2 and Com.3 have a CAF only within 11.5% and 9.5% of the CAF of natural light respectively.

[0119] It will be appreciated that each of devices Dev.3, Dev.4, and Dev.5 thus produces white light that is closer to being similar to natural light in this wavelength region, where human non-visual perception measured by CAF (circadian action factor) or melanopsin ratio (MR) is most affected and this may be beneficial to human well-being.

[0120] Turning to the intensity roll-off (tail) of the spectrum in the orange to red wavelength region of the spectrum (i.e., for wavelengths longer than approximately 570 nm). For Dev.3, the maximum peak intensity (I max Dev.3) is approximately 7.3 and this occurs at a wavelength of approximately 630 nm. The intensity (I) drops to half of this value (1 / 2I RO Dev.3) at a wavelength of approximately 690 nm (λ max Dev.3).

[0121] For Dev.4, the maximum peak intensity (I max Dev.4) is approximately 6.8 and this occurs at a wavelength of approximately 625 nm. The intensity (I) drops to half of this value (1 / 2I RO Dev.4) at a wavelength of approximately 680 nm (λ max Dev.4).

[0122] For Dev.5, the maximum peak intensity (I max Dev.5) is approximately 7.0 and this occurs at a wavelength of approximately 605 nm. The intensity (I) drops to half this value (1 / 2I RO Dev.5) at a wavelength (λ max Dev.5) of approximately 650 nm.

[0123]

[0124]

[0125]

[0126]

[0127] Referring to Tables 6, 7 and 8, it should be noted that device Dev.3 has an efficacy of 109 lm / W and produces white light with a CRI Ra greater than 95 (95.9), where each of CRI R1 to CRI R15 is 90 or higher (91.8 to 99.3). In contrast, device Dev.4 has an efficacy of 149 lm / W and produces white light with a CRI Ra greater than 95 (95.6), where each of CRI R1 to CRI R8 and CRI R10 to CRI R15 is 90 or higher, and CRI R9 (corresponding to "saturated red") is greater than 50 and less than 90 (77.8). In contrast, device Dev.5 has an efficacy of 120 lm / W and produces white light with a CRI Ra greater than or equal to 85 (85.0), where each of CRI R1 to CRI R7 and CRI R10 to CRI R15 is 90 or higher, and CRI R8 (corresponding to "magenta") is less than 72 (60.0), while CRI R9 (corresponding to "saturated red") is greater than 10 and less than 90 (11.9). Additionally, it should be noted that while the quality of the light produced by Dev.4 and Dev.5 is substantially the same as that of Dev.3, the efficacy is increased by approximately 20% and 50% respectively.

[0128] Testing Data of 4000K Full - Spectrum White - Light Emitting Device

[0129] Tables 9, 10 and 11 tabulate the measured optical test data of the 4000K white light emitting device Dev.6 and the known 4000K CRI90 comparative device Com.4. The light emitting device Dev.6 includes a main wavelength λ d1 = 443 nm, λ d2 = 451 nm and λ d3A combination of 2835 packages of three LED chips with a wavelength of 457 nm and including GAL520 and CASN650 phosphors. The comparative device Com.4 includes a known 2835 packaged white light emitting device that uses a narrowband excitation source and has a nominal CRI Ra of 90.

[0130] Figure 8 Shows the intensity spectra, normalized intensity (normalized to CIE 1931 XYZ relative luminance Y = 100) versus wavelength (nm) for the following three: (i) Dev.6 (solid line), (ii) Com.4 (dotted line), and (iii) Planck spectrum (dashed line) for a CCT of 4000K that is nominally the same as Dev.6 and Com.4. Spectral analysis indicates that within the wavelength range of 430 nm to 520 nm (blue to cyan), the maximum percentage normalized intensity deviation I maxdev , that is, the maximum difference between the normalized intensity of the light emitted by device Dev.6 and the normalized intensity of the light of the blackbody curve (bbc) at the same correlated color temperature (4000K). This is to be contrasted with the known comparative device Com.2, which uses a narrowband excitation source for white light that produces a maximum percentage deviation I maxdev (at a wavelength of approximately 450 nm) of the normalized intensity of approximately 90%. In addition, as can be seen from Table 6, the Dev.6 device produces white light with a CAF of 0.4% that is equal to that of natural light (bbc for CCT 4000K). In contrast, the comparative device Com.3 has a CAF that is only within 7.0% of that of natural light.

[0131] It will be appreciated that device Dev.6 produces white light that is closer to being similar to natural light in this wavelength region, where human non-visual perception measured by CAF (circadian action factor) or melanopsin ratio (MR) is most affected and this may be beneficial to human well-being.

[0132] Turning to the intensity roll-off (tail) of the spectrum in the orange to red wavelength region of the spectrum (i.e., for wavelengths longer than approximately 570 nm). For Dev.6, the maximum peak intensity (I max Dev.6) is approximately 5.9 and this occurs at a wavelength of approximately 630 nm. The intensity (I) drops to half of this value (1 / 2I RO Dev.6) at a wavelength of approximately 685 nm (λ max Dev.6).

[0133]

[0134]

[0135]

[0136] Referring to Tables 9, 10 and 11, it should be noted that the device Dev.6 has an efficacy of 117 lm / W and produces white light with a CRI Ra greater than 95 (95.9), where each of CRI R1 to CRI R15 is 90 or higher (91.8 to 99.3).

[0137] Testing Data of 5000K Full - Spectrum White - Light Emitting Device

[0138] Tables 12, 13 and 14 tabulate the measured optical test data of 5000K white light emitting devices Dev.7 and Dev.8 and known 5000K CRI90 and CRI80 comparative devices Com.5 and Com.6, respectively, and illustrate the effect on the efficacy of reducing the red spectral content while maintaining the blue and cyan spectral contents.

[0139] The light emitting devices Dev.7 and Dev.8 each include a 2835 package containing three LED chips with peak wavelengths λ d1 = 443 nm, λ d2 = 451 nm and λ d3 = 457 nm. Dev.7 includes a combination of GAL520 and CASN650 phosphors, while device Dev.8 includes a combination of GAL520, GAL530, CASN625 and CASN650 phosphors. The comparative device Com.5 includes a known 2835 package white light emitting device using a narrowband excitation source and having a nominal CRI Ra of 90. Com.6 includes a known 2835 package white light emitting device using a narrowband excitation source and having a nominal CRI Ra of 80.

[0140] Figure 9a The intensity spectra, normalized intensity (normalized to CIE 1931 XYZ relative luminance Y = 100) versus wavelength (nm) of the following three are shown: (i) Dev.7 (solid line), (ii) Com.5 (dotted line), and (iii) Planck spectrum (dashed line) for a CCT of 5000K that is nominally the same as Dev.7 and Com.5. Spectral analysis indicates that within the wavelength range of 430 nm to 520 nm (blue to cyan), the maximum percentage normalized intensity deviation I between the normalized intensity of the light emitted by device Dev.7 and the normalized intensity of the light of the CIE standard illuminant D of the same correlated color temperature (5000K) is about 50%. maxdev This is to be contrasted with the known comparative device Com.5, which exhibits a maximum percentage deviation I of the normalized intensity of about 115% maxdev (at a wavelength λ of about 450 nm maxdevA narrowband excitation light source for white light (below). In addition, as can be seen from Table 12, device Dev.7 produces white light with a CAF within 2.1% of the CAF of natural light (for CIE D at CCT 5000K). In contrast, comparative device Com.5 has a CAF only within 12.6% of the CAF of natural light.

[0141] Figure 9b Show the intensity spectra, normalized intensity (normalized to CIE 1931 XYZ relative luminance Y = 100) against wavelength (nm) for the following three: (i) Dev.8 (solid line), (ii) Com.6 (dotted line), and (iii) Planck spectrum (dashed line) for a CCT of 5000K nominally the same as Dev.8 and Com.6. Spectral analysis indicates that within the wavelength range of 430 nm to 520 nm (blue to cyan), the maximum percentage normalized intensity deviation I between the normalized intensity of the light emitted by device Dev.8 and the normalized intensity of the light of CIE standard illuminant D of the same correlated color temperature (5000K) is about 20%. maxdev . This is to be contrasted with the known comparative device Com.6, which uses a narrowband excitation light source for white light that produces a maximum percentage normalized intensity deviation of about 140% (at a wavelength λ of about 450 nm maxdev below). In addition, as can be seen from Table 12, device Dev.8 produces white light with a CAF within 2.0% of the CAF of natural light (for CIE D at CCT 5000K). In contrast, comparative device Com.6 has a CAF only within 13.1% of the CAF of natural light.

[0142] It will be appreciated that each of devices Dev.7 and Dev.8 produces white light that is closer to being similar to natural light in this wavelength region, where human non-visual perception measured by CAF (circadian action factor) or melanopsin ratio (MR) is most affected and this may be beneficial to human well-being.

[0143] Turning to the intensity roll-off (tail) of the spectrum in the orange to red wavelength region of the spectrum (i.e., for wavelengths longer than about 570 nm). For Dev.7, the maximum peak intensity (I max Dev.7) is about 4.9 and this occurs at a wavelength of about 625 nm. The intensity (I) drops to half of this value (1 / 2I RO Dev.7) at a wavelength of about 685 nm (λ max Dev.7).

[0144] For Dev.8, the maximum peak intensity (I maxDev.8) is approximately 5.6 and this occurs at a wavelength of approximately 590 nm. The intensity (I) drops to half of this value (1 / 2I RO at a wavelength (λ max of approximately 650 nm for Dev.8).

[0145]

[0146]

[0147]

[0148] Referring to Tables 12, 13 and 14, it should be noted that Device Dev.7 has an efficacy of 117 lm / W and produces white light with a CRI Ra greater than 95 (98.5), where each of CRI R1 to CRI R15 is 90 or higher (93.5 to 99.0). In contrast, Device Dev.8 has an efficacy of 152 lm / W and produces white light with a CRI Ra greater than 80 (83.9), while CRI R8 (corresponding to "red-violet") is less than 72 (62.6), and CRI R9 (corresponding to "saturated red") is greater than zero and less than 90 (1.3). In addition, it should be noted that although the quality of the light produced by Dev.8 is substantially the same as that of the light of Dev.7, the efficacy increase is substantially about 30% and is comparable to Com.6.

[0149] LED Filament White - Light Emitting Device

[0150] Although the white light emitting device according to an embodiment of the present invention has been described with reference to remote phosphors and encapsulated white light emitting devices, it will be understood that the class of white light emitting devices encompasses LED filament white light emitting devices. Tests have confirmed that the white light emitting device in the form of an LED filament according to an embodiment of the present invention has similar spectral characteristics and provides the same benefits and advantages as the white light emitting devices described above.

[0151] Figure 10 A side view of an LED filament A series lamp (bulb) 10100 for generating full-spectrum white light having a CCT (correlated color temperature) in the range of 1800 K to 6800 K is illustrated. According to the present invention, the LED filament lamp 10100 includes a connector base 10102, a light-transmissive glass tube 10104; a glass LED filament support (rod) 10106 and four LED filaments (white light emitting devices) 1010.

[0152] Now referring to Figure 11a and 11b describe an LED filament 1110 according to an embodiment of the present invention, Figure 11a and 11bShows a cross-sectional side view through C-C and a partially cut-away plan view of the LED filament. The LED filament 1110 may include a light-transmissive circuit board (substrate) 11108 having an array of solid-state broadband excitation sources 1120 mounted on a front face 11110. The broadband excitation source is configured to generate broadband blue excitation light having a peak wavelength λ in the blue wavelength region of the visible spectrum with a FWHM from 25 nm to 50 nm, i.e., from 420 nm to 470 nm. In the illustrated embodiment, the broadband excitation source 1120 consists of non-encapsulated broadband blue LED dies (such as the MQW InGaN / GaN LED dies described herein) mounted directly to the substrate. In other embodiments, each of the broadband excitation sources 1120 may consist of a combination of at least two narrowband blue LED dies having different respective peak wavelengths λ d , λ d1 , λ d2 mounted directly to the substrate.

[0153] In the illustrated embodiment, the substrate 11108 is planar and has an elongated form (strip), where the broadband excitation sources 1120 are configured as a linear array along the length of the front face 11110 of the substrate.

[0154] Typically, each LED filament may include 25 excitation sources (LED dies) having a total nominal power of about 2 W.

[0155] The preferably at least semi-transparent substrate 11108 may include any light-transmissive material having a transmittance of 10% or greater for visible light, such as, for example, a glass or plastic material such as polypropylene, silicone, or acrylic resin. The substrate 11108 may further include conductive rails 11112 on the front face 11110 configured with a desired circuit configuration for electrically connecting the excitation sources 1120. As illustrated, the excitation sources 1120 may be electrically connected in series as a string. As shown, the excitation sources 1120 may be electrically connected to the conductive rails 11112 using bonding wires 11114. In other embodiments, the excitation sources 1120 may be directly connected to each other by means of bonding wires, thereby obviating the need for conductive rails. In still other embodiments, the excitation sources 1120 may include surface-mount or flip-chip LEDs mounted to the conductive rails. The substrate 11108 may include electrodes 11116 at corresponding ends for applying power to the LED filament 1110.

[0156] According to an embodiment of the present invention, the LED filament 1110 further includes a photoluminescent wavelength conversion material 1166 that at least covers the front surface 11110 of the substrate and the excitation source 1120. According to an embodiment of the present invention, the photoluminescent wavelength conversion material 1166 includes a combination of a green to yellow photoluminescent material and optionally an orange to red photoluminescent material. To ensure that the light emitted from the front and the back of the LED filament is substantially the same color, the LED filament 1110 may further include, as shown, a photoluminescent wavelength conversion material 11118 that covers the back surface 11120 of the substrate. The photoluminescent wavelength conversion material 11118 may include the same photoluminescent material as the photoluminescent wavelength conversion material 1166.

[0157] As described above, a particular advantage of the present invention is that a full-spectrum white light-emitting device according to an embodiment of the present invention can produce full-spectrum light that is close to natural light in the blue to cyan wavelength region (430 nm to 520 nm) of the spectrum, where human non-visual perception measured by CAF (circadian action factor) or melanopsin ratio (MR) is most affected. The lighting industry has had much discussion about blue light stimulation and its impact on the circadian rhythm. The amount of blue to cyan light in a light source affects melatonin secretion, which may affect the circadian rhythm cycle. High levels of blue to cyan light inhibit melatonin secretion, thus energizing the human body. Low levels of blue light do not inhibit melatonin secretion, thus relaxing the human body. One metric used to estimate this non-visual effect is the CAF circadian action factor, which is typically modulated by the blue light content within a day. At noon, the sun has a high CCT and a relatively high blue to cyan light content. Sunrise and sunset have a lower CCT and a lower blue to cyan light content. The CAF values of natural light at different CCTs are a good measure of the lighting deviation from natural light in the blue to cyan region where human mood, health, or well-being is affected.

[0158] In addition, a further advantage of the full-spectrum white light-emitting device of the present invention is that, by appropriate selection of the peak emission wavelength / FWHM of the orange-to-red photoluminescent material, the device produces white light with a spectrum having a roll-off (tail) in the orange-to-red wavelength region, wherein the intensity decreases from its maximum value in the orange-to-red wavelength region of the spectrum to about 50% of the maximum value at wavelengths from about 645 nm to about 695 nm. This spectral characteristic (tail) reduces the light intensity (photon count) in the red wavelength region of the spectrum, at which wavelengths the photopic response of the eye is low and thereby increases the device efficiency. Test data have confirmed that the full-spectrum white light-emitting device according to the present invention can produce white light having a CRI Ra of at least 90 and an efficiency equal to or exceeding that of known CRI80 devices, while having only a reduction in CRI R9 and CRI R8. Despite this reduction in the values of CRI R9 and CRI R8, due to the sensitivity of the eye in the red wavelength region of the spectrum, the perceived quality of the light produced by the device is not adversely affected.

[0159] In summary, it will be appreciated that embodiments of a light-emitting device according to the present invention including a broadband solid-state excitation source achieve a full-spectrum white light-emitting device characterized by white light having a color temperature in the range of 1800K to 6800K by generating under one or more of the following conditions: (i) in the wavelength range from about 430 nm to about 520 nm, the white light has a maximum percentage intensity deviation from the intensity of the blackbody curve or the light of CIE standard illuminant D of the same correlated color temperature of less than at least one of 60%, 50%, 40%, 30%, 20%, and 10%, (ii) the spectrum has a CAF within 5%, 4%, 2%, or 1% of the blackbody curve / CIE standard illuminant D, (iii) CRI R9 and / or CRI R8 is less than 90, (iv) the intensity of the spectrum decreases from its maximum value in the orange to red wavelength region of the spectrum to about 50% of the maximum value at wavelengths from about 645 nm to about 695 nm, (v) the intensity of the spectrum decreases from its maximum value in the orange to red wavelength region of the spectrum to about 50% of the maximum value at wavelengths from about 645 nm to about 695 nm and has a CRI Ra greater than or equal to 85, CRI R1 to CRI R7 and CRI R10 to CRI R15 greater than or equal to 90, CRI R8 less than 72, and CRI R9 greater than 10 and less than 90, (vi) the intensity of the spectrum decreases from its maximum value in the orange to red region of the spectrum to about 50% of the maximum value at wavelengths from about 645 nm to about 695 nm and has a CRI Ra greater than or equal to 95, CRI R1 to CRI R8 and CRIR10 to CRI R15 greater than or equal to 90, and CRI R9 greater than 50 and less than 90, and (vii) the intensity of the spectrum decreases from its maximum value in the orange to red region of the spectrum to about 50% of the maximum value at wavelengths in the range from about 645 nm to about 695 nm and has a CRI Ra greater than or equal to 95 and CRI R1 to CRI R15 greater than or equal to 90.

[0160] Although the present invention has been described in detail, it will be apparent to those skilled in the art that various changes and modifications can be made and equivalents can be employed without departing from the present invention. It should be understood that the present invention is not limited to the construction details, component arrangements, and / or methods set forth in the above description or illustrated in the drawings. In addition, the figures are merely illustrative and not restrictive. The subject headings and subheadings are for the convenience of the reader only. They should not and cannot be construed as having any substantial meaning, significance, or interpretation, and should not and cannot be considered as indicating that all information related to any particular subject will be found under any particular heading or subheading or be limited to any particular heading or subheading. Therefore, the present invention should not be constrained or limited except in accordance with the following claims and their legal equivalents. Although the present invention has been specifically described with reference to certain of its embodiments, it will be readily apparent to those of ordinary skill in the art that changes and modifications in form and detail can be made without departing from the spirit and scope of the present invention.

[0161] Although the present invention has been specifically described with reference to certain of its embodiments, it will be readily apparent to those of ordinary skill in the art that changes and modifications in form and detail can be made without departing from the spirit and scope of the present invention.

Claims

1. A full-spectrum white light emitting device, comprising: A photoluminescent material for generating light having peak emission wavelengths from 490 nm to 570 nm and from 620 nm to 650 nm; and A broadband solid-state excitation source for generating broadband excitation light having an FWHM of at least 30 nm and a peak wavelength from 420 nm to 480 nm, The broadband solid-state excitation source comprising: A plurality of narrowband LEDs for generating blue light emissions of multiple different wavelengths; or A broadband LED having a plurality of different quantum wells in its active region for generating multiple blue wavelength emissions; Wherein the device is for generating white light having a spectrum, and in the wavelength range from 430 nm to 520 nm, the maximum percentage intensity deviation of the white light from the intensity of the blackbody curve or the light of CIE standard illuminant D is less than 10%.

2. The light emitting device according to claim 1, wherein the intensity of the spectrum decreases from its maximum value in the orange to red wavelength region of the spectrum to 50% of the maximum value at wavelengths from 645 nm to 695 nm, at wavelengths from 645 nm to 665 nm, at wavelengths from 665 nm to 690 nm, or at wavelengths from 680 nm to 695 nm.

3. The light emitting device according to claim 1 or claim 2, wherein the white light has a circadian action factor within 5% of the circadian action factor of the blackbody curve or CIE standard illuminant D.

4. The light emitting device according to claim 1 or claim 2, wherein the white light has a CRI Ra of at least 90 or at least 95.

5. The light emitting device according to claim 1 or claim 2, wherein the broadband excitation light has an FWHM from 30 nm to 70 nm or at least 50 nm.

6. The light emitting device according to claim 1 or claim 2, wherein the white light has a correlated color temperature from 2700 K to 3000 K and the device has an efficacy of at least 102 lm / W.

7. The light emitting device according to claim 1 or claim 2, wherein the white light has a correlated color temperature from 4000 K to 6800 K and the device has an efficacy of at least 110 lm / W.

8. The light emitting device according to claim 1 or claim 2, wherein the device is one of a surface mount device, an on-board chip, and a filament.

9. A full-spectrum white light emitting device, comprising: A photoluminescent material for generating light having peak emission wavelengths from 490 nm to 570 nm and from 620 nm to 650 nm; and A broadband solid-state excitation source for generating broadband excitation light having an FWHM of at least 30 nm and a peak wavelength from 420 nm to 480 nm, Wherein, the broadband solid-state excitation source comprises: A plurality of narrowband LEDs for generating blue light emissions of multiple different wavelengths; or A broadband LED having a plurality of different quantum wells in its active region for generating multiple blue wavelength emissions; wherein the device is configured to generate white light having a spectrum, the intensity of which decreases from a maximum value in the orange to red wavelength region of the spectrum to 50% of the maximum value at wavelengths from 645 nm to 695 nm, from 645 nm to 665 nm, from 665 nm to 690 nm, or from 680 nm to 695 nm.

10. The light-emitting device according to claim 9, wherein the white light has a CRI Ra of at least 90 or at least 95.

11. The light-emitting device according to claim 9 or claim 10, wherein the device is configured to generate white light having a CRI R9 greater than 10 and less than 90 or greater than 50 and less than 90.

12. The light-emitting device according to claim 9 or claim 10, wherein the device is configured to generate white light having a CRI R8 less than 90 or less than 72.

13. A full-spectrum white light-emitting device, comprising: a photoluminescent material configured to generate light having peak emission wavelengths from 490 nm to 570 nm and from 620 nm to 650 nm; and a broadband solid-state excitation source configured to generate broadband excitation light having an FWHM of at least 30 nm and a peak wavelength from 420 nm to 480 nm, wherein the broadband solid-state excitation source comprises: a plurality of narrowband LEDs configured to generate blue light emissions at a plurality of different wavelengths; or a broadband LED having a plurality of different quantum wells in an active region thereof to generate a plurality of blue wavelength emissions; wherein the device is configured to generate white light having a spectrum with a circadian action factor within 5% of the circadian action factor of the blackbody curve or CIE standard illuminant D.

14. An LED filament, comprising: a light-transmissive substrate; an array of broadband solid-state excitation sources mounted on a surface of the light-transmissive substrate; and a photoluminescent material configured to generate light having peak emission wavelengths from 490 nm to 570 nm and from 620 nm to 650 nm; and wherein the broadband solid-state excitation source is configured to generate broadband excitation light having an FWHM of at least 30 nm and a peak wavelength from 420 nm to 480 nm, wherein the broadband solid-state excitation source comprises: a plurality of narrowband LEDs configured to generate blue light emissions at a plurality of different wavelengths; or a broadband LED having a plurality of different quantum wells in an active region thereof to generate a plurality of blue wavelength emissions; and wherein in a wavelength range from 430 nm to 520 nm, the maximum percentage intensity deviation of the white light generated by the LED filament from the intensity of the light of the blackbody curve or CIE standard illuminant D is less than 10%.

15. An LED filament, comprising: a light-transmissive substrate; an array of broadband solid-state excitation sources mounted on a surface of the light-transmissive substrate; and a photoluminescent material configured to generate light having peak emission wavelengths from 490 nm to 570 nm and from 620 nm to 650 nm; and wherein the broadband solid-state excitation source is used to generate broadband excitation light having an FWHM of at least 30 nm and a main wavelength ranging from 420 nm to 480 nm, wherein the broadband solid-state excitation source comprises: a plurality of narrowband LEDs for generating blue light emissions of a plurality of different wavelengths; or a broadband LED having a plurality of different quantum wells in an active region thereof for generating a plurality of blue wavelength emissions; and wherein the LED filament is used to generate white light, and the intensity of the spectrum of the white light decreases from its maximum value in the orange to red wavelength region of the spectrum to 50% of the maximum value at wavelengths from 645 nm to 695 nm, at wavelengths from 645 nm to 665 nm, at wavelengths from 665 nm to 690 nm, or at wavelengths from 680 nm to 695 nm.

16. An LED filament, comprising: a light-transmitting substrate; an array of broadband solid-state excitation sources mounted on a surface of the light-transmitting substrate; and a photoluminescent material for generating light having peak emission wavelengths ranging from 490 nm to 570 nm and from 620 nm to 650 nm; and wherein the broadband solid-state excitation source is used to generate broadband excitation light having an FWHM of at least 30 nm and a main wavelength ranging from 420 nm to 480 nm, wherein the broadband solid-state excitation source comprises: a plurality of narrowband LEDs for generating blue light emissions of a plurality of different wavelengths; or a broadband LED having a plurality of different quantum wells in an active region thereof for generating a plurality of blue wavelength emissions; and wherein the LED filament is used to generate white light having a spectrum with a circadian action factor within 5% of the circadian action factor of a blackbody curve or CIE standard illuminant D.

17. The LED filament according to claim 14 or claim 15 or claim 16, wherein the white light has a CRI Ra of at least 90 or at least 95.

18. The LED filament according to claim 14 or claim 15 or claim 16, wherein the LED filament is used to generate white light having a CRI R9 greater than 10 and less than 90 or greater than 50 and less than 90.

Images