Lighting device with LEDs of different chromaticities

Abstract

a second LED generating light having a peak emission wavelength between 500 nm and 565 nm (i.e., green); a third LED generating light having a dominant wavelength between 430 nm and 480 nm (i.e., violet to blue); and a fourth LED generating white light having a CCT between 1800 K and 5000 K, wherein the first LED comprises a first LED chip generating light having a dominant wavelength between 400 nm and 480 nm and a phosphor-converted LED comprising a narrowband red phosphor having a FWHM of less than 55 nm, wherein the light generated by the device comprises a combination of light generated by the first, second, third, and fourth LEDs, and the CCT of the light generated by the device is tunable from 1800 K to 8000 K by independently controlling power to the first, second, third, and fourth LEDs.

Description

[Technical Field]

[0001] Cross-Reference to Related Applications This application claims priority from (i) International Patent Application No. PCT / CN2022 / 120875, filed September 23, 2022, entitled "Phosphor-Converted Red LEDs and Color-Tunable Multi-LED Packaged Light Emitting Devices," and (ii) U.S. Provisional Patent Application No. 63 / 299,408, filed January 13, 2022, entitled "Phosphor-Converted Red LEDs," each of which is incorporated herein by reference in its entirety. [Background technology]

[0002] FIELD OF THE INVENTION A first aspect of the present invention generally relates to phosphor-converted (PC) color LEDs (Light Emitting Diodes) that emit light of a selected color. More specifically, a preferred embodiment of the present invention relates to phosphor-converted red LEDs (PC red LEDs). Another aspect of the present invention relates to color-tunable multi-LED (Light Emitting Diode) lighting devices that can emit light having a color temperature between 2200K and 6500K, optionally from red to blue. More specifically, but not exclusively, the present invention relates to color-tunable multi-LED packages and packaging configurations that utilize PC red LEDs.

[0003] Background of the Invention Phosphor-converted color LEDs (light-emitting diodes), also known as "PC color LEDs," typically comprise a blue LED chip and a phosphor (photoluminescent) material. The phosphor material converts nearly all of the excitation light generated by the LED chip into light of a selected color, such as green, yellow, orange, or red, through a process of photoluminescence wavelength conversion. Because all of the light generated by the LED chip is converted into light of a selected color, these PC color LEDs can also be referred to as fully phosphor-converted (FPC) color LEDs. PC color LEDs are contrasted with PC white LEDs, in which only partial conversion of the blue light generated by the LED chip occurs, with the remaining blue light ultimately contributing to the white light emission. The light generated by PC color LEDs is generally broadband, with a FWHM (full width at half maximum) of 70 nm to 120 nm, depending on the phosphor composition. The color (peak emission wavelength) of the light generated by PC color LEDs depends on the composition of the phosphor material.

[0004] PC color LEDs are contrasted with direct-emitting "color LEDs," which emit nearly monochromatic light (FWHM ≒ 20-25 nm) directly without photoluminescence (phosphor) wavelength conversion, and the color of the light is determined by the semiconductor material system of the LED chip. For example, direct-emitting green LEDs use InGaN (indium gallium nitride) LED chips, direct-emitting red LEDs use AlInGaP (aluminum indium gallium phosphide) LED chips, and direct-emitting blue LEDs use InGaN (indium gallium nitride) LED chips.

[0005] Due to their narrow-band emission characteristics, direct-emitting red, green, and blue color LEDs find particular utility for improving the color gamut of color-tunable multi-LED packages (multi-LED package lighting devices) for displays and general lighting applications, for example, in RGB (Red, Green, Blue) systems such as display backlighting. Current color-tunable multi-LED packages generally include red, green, and blue direct-emitting "color LED" chips.

[0006] A known color-tunable multi-LED package lighting device (Surface Mount Device - SMD) is shown in FIGS. 1A and 1B, where FIG. 1A shows a top view and FIG. 1B shows a side cross-sectional view of the multi-LED package taken along line AA. The known multi-LED package 1 comprises a lead frame 2 for supplying power to red, green, and blue direct-emitting LED chips 3R, 3G, and 3B. A housing 4 is molded onto the lead frame and comprises a single cavity (recess) 5 (e.g., circular in shape). The red, green, and blue direct-emitting LED chips 3R, 3G, and 3B are mounted on the bottom (floor) of the cavity 5 and electrically connected to the lead frame 2. To protect the LED chips 3 from the external environment, the cavity 5 is typically filled with a light-transmitting encapsulant such as a silicone material. Portions of the lead frame 2 extend laterally to the outer edges of the housing 4, forming respective electrical terminals 7R, 7G, 7B, 8R, 8G, and 8B along opposing edges and the bottom of the package, allowing for independent power supply to the anodes (positive electrodes) and cathodes (negative electrodes) of each of the red, green, and blue direct-emitting color LED chips 3R, 3G, and 3B. A PC white LED package, in contrast to the direct-emitting color LED chips, comprises a direct-emitting blue LED chip and a photoluminescent material, typically a phosphor material, which converts a portion of the blue excitation light generated by the LED chip, with the remaining blue light ultimately contributing to the white emitted light. The phosphor material may be embedded in a light-transmitting encapsulant used to fill the cavity.

[0007] However, a drawback of multi-LED packages based on direct-emitting color LEDs is that, because they are based on different semiconductor material systems, each color LED chip generally has different characteristics, such as thermal stability, aging characteristics, drive requirements, etc. As a result of these different characteristics, the light output of red, green, and blue LEDs varies differently from one another with temperature and time. The color composition of the light emitted by RGB systems based on color LEDs consequently varies with temperature and time, and such LED systems may use complex drive circuits to compensate for these different characteristics, which can result in additional costs during manufacturing and maintenance. In contrast, PC color LEDs eliminate the need for such measures because they are all based on LED chips with the same semiconductor material and have the same drive requirements, thermal stability, etc.

[0008] Current PC red LEDs generally use broadband red nitride phosphors and have peak emission wavelengths between 620 nm and 630 nm. For many applications, including display backlighting, automotive brake lights and turn signals, traffic signals, emergency vehicle lights, etc., it would be desirable for PC red LEDs to produce narrowband red light with a FWHM similar to or shorter than that of direct-emitting color LEDs (FWHM = 20-25 nm).

[0009] For example, K2SiF6:Mn 4+ (KSF), K2TiF6:Mn 4+ (KTF), and K2GeF 6: Mn 4+Narrow-band red phosphors, such as manganese-activated fluoride-based phosphors like (KGF), have very narrow red emission spectra (less than 10 nm full width at half maximum for their main emission line spectrum), making them highly desirable for achieving high brightness and luminous efficiency in PC white LEDs (approximately 25% brighter than broad-band red phosphors like europium-activated red nitride phosphor materials like CASN-CaAlSiN3:Eu). While narrow-band red fluoride phosphors may at first glance seem an ideal choice for PC red LEDs, they have drawbacks that make their use in PC red LEDs challenging. For example, the absorption efficiency of narrow-band red fluoride phosphors is significantly lower (typically about 10 times lower) than that of red nitride phosphors currently used in PC red LEDs. Therefore, achieving complete conversion of blue light to red light requires a 5- to 20-fold greater amount of narrow-band red fluoride phosphor than that of red nitride phosphors. Such an increase in the overall amount of phosphor used significantly increases the cost of manufacturing, and this makes narrow-band red fluoride phosphors prohibitively expensive for use in PC red LEDs, especially since narrow-band red fluoride phosphors are significantly more expensive (e.g., at least five times more expensive) than europium-activated red nitride phosphors.

[0010] Furthermore, the relatively low absorption efficiency of narrow-band red fluoride phosphors can result in unconverted blue light, so-called "blue light pass," that is generated by the LED chip and ultimately becomes luminescent light. Unconverted blue light reduces the color purity of the red light emission. While "blue light pass" may be acceptable in white light systems, such as display backlighting, where blue light is a component of white light, for applications requiring "pure red" (nearly monochromatic) light, "blue light pass" reduces the color purity of the red light and is therefore highly undesirable.

[0011] Another problem with utilizing only narrow-band red fluoride phosphors is that although narrow-band red fluoride phosphors provide narrow-band red emission, they readily react with water or moisture, causing damage to the manganese dopant, resulting in a degradation or loss of photoluminescence emission (i.e., quantum efficiency) of the phosphor. Furthermore, the reaction of fluoride-based compounds with water can generate highly corrosive hydrofluoric acid, which can react with LED packaging materials, such as bond wires, resulting in premature failure of the device. Summary of the Invention [Problem to be solved by the invention]

[0012] The present invention is intended to address and / or overcome the above-mentioned limitations by presenting new designs and methods not previously contemplated or possible with known configurations. More specifically, preferred embodiments of the present invention relate to, but are not limited to, improvements regarding increasing the luminous efficacy of color-tunable multi-LED lighting devices through a novel phosphor packaging structure that effectively improves the blue absorption efficiency of narrow-band red fluoride phosphors; increasing the color purity of PC red LEDs by reducing "blue light pass-through"; reducing the amount of narrow-band red fluoride phosphor used; and isolating the narrow-band red fluoride phosphor from water / moisture in the surrounding environment. [Means for solving the problem]

[0013] A first aspect of the present invention generally relates to a PC red LED based on an InGaN-based blue-emitting LED, which contains a combination of a narrow-band red fluoride phosphor (e.g., a manganese-activated fluoride narrow-band red phosphor) and a red phosphor with higher absorption efficiency, such as a broad-band red phosphor. The inclusion of a broad-band red phosphor with higher absorption efficiency than the narrow-band red fluoride phosphor converts blue light not converted by the narrow-band red fluoride phosphor into red light, significantly reducing or even eliminating blue light transmission and improving color purity. Thus, the inclusion of a red phosphor with higher absorption efficiency than the narrow-band red fluoride phosphor can be said to compensate for the lower absorption efficiency of the narrow-band red fluoride phosphor.

[0014] The broadband red phosphor and the narrowband red fluoride phosphor can be provided in the same (single) layer, for example as a mixture, which can improve the ease with which the PC red LED can be manufactured, and thus reduce the manufacturing cost and time.

[0015] In another preferred embodiment, the broadband red phosphor and the narrowband red fluoride phosphor can each be provided in their own layer, with the layer containing the narrowband red fluoride phosphor being positioned closer to the LED chip than the layer containing the broadband red phosphor. This arrangement effectively increases the absorption efficiency of the narrowband red fluoride phosphor and significantly reduces the amount of narrowband red fluoride phosphor used. The layer containing the narrowband red fluoride phosphor can be in direct contact with at least one of the light-emitting surfaces of the LED chip. The broadband red phosphor can be in direct contact with the layer containing the narrowband red fluoride phosphor and completely cover (seal) this layer. This configuration / arrangement can provide environmental protection for the layer containing the narrowband red fluoride phosphor and improve the reliability of the entire device.

[0016] According to one aspect of the present invention, there is provided a red light-emitting device, the red light-emitting device comprising: an LED chip having a peak emission wavelength of 400 nm to 500 nm; and a photoluminescent material, the photoluminescent material including a narrow-band red fluoride phosphor and a broad-band red phosphor.

[0017] In a preferred embodiment, the narrow-band red fluoride phosphor and the broad-band red phosphor can be configured as a single-layer photoluminescent structure. These phosphors can be provided, for example, in the same layer. These phosphors can be provided in a single layer, typically as a mixture. As used herein, "direct contact" means there is no air gap or photoluminescent layer. In another preferred embodiment, the device can include a light-transmitting passivation layer between the layer and the LED chip. This light-transmitting layer provides passivation for the LED chip, providing a barrier against potential effects of the narrow-band red fluoride phosphor on the LED chip. Such an arrangement can improve device reliability.

[0018] To further improve the absorption efficiency of the narrow-band red fluoride phosphor, the narrow-band red fluoride phosphor can be placed closer to the LED than the broad-band red phosphor. Placing the narrow-band red fluoride phosphor closer to the LED chip effectively increases the absorption efficiency of the narrow-band red fluoride phosphor because it does not have to compete with the broad-band red phosphor for blue photons.

[0019] In a preferred embodiment, the red light-emitting device may comprise a two-layer photoluminescent structure comprising a first layer and a second layer, the first layer containing a narrow-band red fluoride phosphor and disposed adjacent to the LED chip, and the second layer containing a broad-band red phosphor and disposed on and covering the first layer, which may partially or completely cover the first layer.

[0020] Compared to a single-layer photoluminescent structure, a two-layer photoluminescent structure having a first layer containing only, or substantially only (at least 90% by weight) narrow-band red fluoride phosphor covered by a second layer can provide numerous advantages, including, but not limited to: (1) a significant reduction in the amount of narrow-band red fluoride phosphor used (approximately 40% reduction); (2) the second layer provides environmental protection to the first layer, thereby reducing the opportunity for water / moisture to reach and degrade the narrow-band red fluoride phosphor; and (3) a significant reduction, or even elimination, of "blue light pass-through," resulting in better color purity of the red light generated by the device.

[0021] The first layer is in direct contact with at least one light-emitting surface (surface) of the LED chip.

[0022] The second layer can be in direct contact with the first layer.

[0023] To further reduce the amount of narrowband red fluoride phosphor used, the first layer can further comprise particles of a light-scattering material, such as particles of zinc oxide; silicon dioxide; titanium dioxide, magnesium oxide; barium sulfate; aluminum oxide, and combinations thereof.

[0024] The narrow band red fluoride phosphor is K2SiF6:Mn 4+ , K2GeF6:Mn 4+ , and K2TiF6:Mn 4+ Alternatively, K2SiF6:Mn 4+ , K2GeF6:Mn 4+ , and K2TiF6:Mn 4+ can be selected from the group consisting of:

[0025] To reduce the FWHM of the red emission generated by the device, the peak emission wavelength of the broadband red phosphor can be selected to be approximately the same as the peak emission wavelength of the narrowband red fluoride phosphor. In a preferred embodiment, the peak emission wavelength of the broadband red phosphor can be within 5 nm of the peak emission wavelength of the narrowband red fluoride phosphor. The broadband red phosphor can have a peak emission wavelength of 620 nm to 640 nm and have the general composition AAlSiN3:Eu 2+ where A is at least one of Ca, Sr, or Ba.

[0026] In preferred embodiments, the red light emitting device generates red light having a color purity of at least 90% and a FWHM of less than 30 nm, a FWHM of less than 20 nm, or a FWHM of less than 10 nm.

[0027] According to another aspect of the present invention, a red light emitting device is contemplated, comprising: an LED flip chip having a peak emission wavelength of 400 nm to 500 nm; and a photoluminescent material in direct contact with at least one light emitting surface of the LED flip chip, the photoluminescent material including a narrowband red fluoride phosphor and a broadband red phosphor.

[0028] In a preferred embodiment, the narrow-band red fluoride phosphor and the broad-band red phosphor can be configured as a single-layer photoluminescent structure. These phosphors can be contained in the same layer. These phosphors can be contained in a single layer, typically as a mixture, which can be in direct contact with at least one light-emitting surface of the LED flip chip.

[0029] In a preferred embodiment, the narrow-band red fluoride phosphor and the broad-band red phosphor can be configured as a two-layer photoluminescent structure. In one preferred embodiment, the red light-emitting device comprises a first layer and a second layer, the first layer containing the narrow-band red fluoride phosphor and adjacent to the LED chip, and the second layer containing the broad-band red phosphor material and overlying the first layer. The first layer can be in direct contact with at least one light-emitting surface (surface) of the LED flip chip, and the second layer can be in direct contact with the first layer.

[0030] Phosphor-converted red LEDs (PC red LEDs) according to preferred embodiments of the present invention find utility as red light sources in light emitting devices (illumination devices), such as RGB (red, green, blue) multi-LED lighting devices comprising a red LED, a green LED, and a blue LED, which find utility in color-tunable light sources.

[0031] Another aspect of the present invention relates generally to color-tunable multi-LED (light-emitting diode) lighting devices capable of producing light having a color temperature ranging from 2200K to 6500K, and optionally from red to blue. More specifically, preferred examples of these include K2SiF6:Mn 4+ , K2GeF6:Mn 4+ , or K2TiF6:Mn 4+The present invention relates to, but is not limited to, PC red LEDs with narrowband red phosphors such as those described herein, and multi-LED lighting devices utilizing the PC red LEDs described herein. According to one aspect, a multi-LED lighting device includes four LEDs: a red LED, a green LED, a blue LED, and a white LED. The lighting device can be a packaged lighting device that includes a package for housing the four LEDs. The red, green, blue, and white LEDs can be CSP (Chip Scale Packaged) LEDs that include LED flip chips. In embodiments where the LEDs are CSP LEDs, the lighting device can include a substrate, such as a circuit board, on which the LEDs are mounted. This type of packaging configuration is referred to as COB (Chip On Board).

[0032] According to one aspect of the present invention, there is provided a lighting device comprising a first LED, a second LED, a third LED, and a fourth LED, wherein the first LED generates light having a peak emission wavelength of 620 nm to 640 nm (i.e., orange to red); the second LED generates light having a peak emission wavelength of 500 nm to 565 nm (i.e., green); the third LED generates light having a dominant wavelength of 430 nm to 480 nm (i.e., violet to blue); and the fourth LED generates light having a CCT (Correlated Color Temperature) of 1800 K to 5000 K. a first LED comprising a first LED chip and a phosphor-converted LED comprising a narrow-band red phosphor, the first LED chip producing light having a dominant wavelength between 400 nm and 480 nm, the narrow-band red phosphor having a FWHM of less than 55 nm, the light produced by the device comprising a combination of light produced by the first, second, third, and fourth LEDs, and a CCT of the light produced by the device that is tunable from 1800 K to 8000 K by independently controlling power to the first, second, third, and fourth LEDs.

[0033] The narrow band red phosphor is K2SiF6:Mn 4+ , K2GeF6:Mn 4+ , or K2TiF6:Mn 4+ It may include at least one of:

[0034] The first LED can further include a broadband red phosphor. The narrowband red phosphor and the broadband red phosphor can be contained in a single layer. Alternatively, the narrowband red phosphor can be contained in a first layer and the broadband red phosphor can be contained in a second layer.

[0035] The first LED is capable of producing light having a color purity of at least 90%.

[0036] The second LED may be a phosphor-converted LED comprising a second LED chip and a green phosphor, where the second LED chip generates light having a dominant wavelength between 400 nm and 480 nm.

[0037] The fourth LED may include a fourth LED chip and a green-red phosphor, where the fourth LED chip generates light having a dominant wavelength of 400 nm to 480 nm.

[0038] The light generated by the device may have a chromaticity within 0.006 Δuv, preferably within 0.003 Δuv, of the blackbody locus for CCTs from 1800K to 6500K, and a CRI Ra of 80 to 98. As used herein, the terms "chromaticity," "color of light," and "color point" of light may be used interchangeably and may refer to the chromaticity / color of light represented by chromaticity coordinates on the CIE chromaticity diagram. Δuv (delta uv) is a metric that quantifies how close light of a given color temperature is to the blackbody locus. As is known, Δuv is the Euclidean distance difference in chromaticity coordinate uv between a test light source and the nearest point on the blackbody locus, and is defined in ANSI_NEMA_ANSLG (American National Standards Institute_National Electrical Manufacturers Association_American National Standard Lighting Group) C78-377-2008: American National Standard for Electric Lamps - Specifications for Chromaticity of Solid-State Lighting Products. Δuv is a measure of the distance of the color point of a light of a given CCT (color temperature) along the iso-CCT line (line of constant color temperature) from the blackbody locus (Planckian locus of blackbody radiation) on the 1976 CIE u,v chromaticity diagram. A positive Δuv value indicates that the color point is above the blackbody locus (i.e., on the 1931 CIE x,y chromaticity diagram, the CIE y is greater than the CIE y value of the blackbody locus), resulting in a yellow / green color shift from the blackbody locus. Negative values indicate that the color point is below the blackbody locus (i.e., on the 1931 CIE x,y chromaticity diagram, the CIE y is less than the CIE y value of the blackbody locus), with a color shift from the blackbody locus towards pink.

[0039] In a preferred embodiment, at least one of the first LED, the second LED, the third LED, or the fourth LED can comprise an LED flip chip or an LED chip comprising multiple LEDs connected in series (LED junctions). LED chips with multiple LED junctions have a larger forward drive voltage, which can be beneficial when the lighting device operates at a power line voltage of 110-240V.

[0040] The lighting device may comprise a package and a housing, the package comprising a lead frame, the housing comprising a first cup (recess) having a first LED, a second cup (recess) having a second LED, a third cup (recess) having a third LED, and a fourth cup (recess) having a fourth LED; the lead frame comprising a common cathode electrode for each cup and a respective anode electrode for each cup.

[0041] The lighting device may include a package and a housing, the package including a lead frame, the housing including a first cup (recess) having a first LED, a second cup (recess) having a second LED, a third cup (recess) having a third LED, and a fourth cup (recess) having a fourth LED; the lead frame including a respective cathode electrode for each cup and a respective anode electrode for each cup. Each cup may include an anode terminal connected to the anode electrode and a cathode terminal connected to the cathode electrode, and the anode terminal and cathode terminal for each recess may be disposed opposite each other on opposite edges of the housing.

[0042] At least one of the first LED, the second LED, the third LED, and the fourth LED may include a chip-scale package.

[0043] According to another aspect, a lighting device comprises four LEDs that emit light having different chromaticities, the light emitted by the device consisting of a combination of light emitted by a first LED, a second LED, a third LED, and a fourth LED, the CCT of the light emitted by the device is tunable from 1800K to 8000K by independently controlling power to the first, second, third, and fourth LEDs, the chromaticity of the light emitted by the device is within 0.006 Δuv, preferably 0.003 Δuv, of the blackbody locus, and at least one of the LEDs comprises a narrowband red phosphor having a FWHM of less than 55 nm.

[0044] This narrow band red phosphor is K2SiF6:Mn 4+ , K2GeF6:Mn 4+ , and K2TiF6:Mn 4+ It may include at least one of:

[0045] In a preferred embodiment, a first LED generates light having a peak emission wavelength between 620 nm and 640 nm (i.e., orange to red); a second LED generates light having a peak emission wavelength between 500 nm and 565 nm (i.e., green); a third LED generates light having a dominant wavelength between 430 nm and 480 nm (i.e., violet to blue); and a fourth LED generates white light having a CCT of at least 1800K.

[0046] According to another aspect, the present invention provides a lighting apparatus comprising a substrate (circuit board) and a plurality of lighting devices as defined herein mounted on the substrate, which may be a linear lighting apparatus.

[0047] This substrate may be a flexible circuit board.

[0048] According to one embodiment, a multi-LED lighting device includes at least three LEDs: a red LED, a green LED, and a white LED. The lighting device can be a packaged lighting device that includes a package for housing the at least three LEDs. The red, green, and white LEDs can be CSP (chip-scale packaged) LEDs that include LED flip chips. In a preferred embodiment where the LEDs are CSP LEDs, the lighting device can include a substrate, such as a circuit board, on which the LEDs are mounted. This type of packaging configuration is called a COB (chip-on-board) configuration.

[0049] According to one aspect of the present invention, there is provided a lighting device comprising: a first LED; a second LED; and a third LED, wherein the first LED generates light having a peak emission wavelength from 620 nm to 640 nm, the second LED generates light having a peak emission wavelength from 500 nm to 565 nm, and the third LED generates light having a CCT of at least 1800 K, and the first LED comprises a phosphor-converted LED comprising an LED chip and a narrow-band red phosphor, wherein the LED chip generates light having a dominant wavelength from 400 nm to 480 nm, and the narrow-band red phosphor has a FWHM of less than 55 nm.

[0050] This narrow band red phosphor is K2SiF6:Mn 4+ , K2GeF6:Mn 4+ , and K2TiF6:Mn 4+ It may include at least one of:

[0051] The first LED can further include a broadband red phosphor. The narrowband red phosphor and the broadband red phosphor can be contained in a single layer. Alternatively, the narrowband red phosphor can be contained in a first layer and the broadband red phosphor can be contained in a second layer.

[0052] The first LED is capable of producing light having a color purity of at least 90%.

[0053] The second LED may be a phosphor-converted LED comprising a second LED chip and a green phosphor, and the second LED chip emits light having a dominant wavelength of 400 nm to 480 nm (i.e., violet to blue).

[0054] The third LED may include a third LED chip and a green-red phosphor, and may generate white light having a CCT of 1800K to 5000K, and the third LED chip may generate light having a dominant wavelength of 400nm to 480nm.

[0055] The lighting device can be a packaged device or a COB device.

[0056] The lighting device may comprise a package and a housing, the package comprising a lead frame; the housing comprising a first cup (recess) having a first LED, a second cup (recess) having a second LED, a third cup (recess) having a third LED, and a fourth cup (recess) having a fourth LED, the lead frame comprising a common cathode electrode for each cup and a respective anode electrode for each cup.

[0057] The lighting device may include a package and a housing, the package including a lead frame, the housing including a first cup (recess) having a first LED, a second cup (recess) having a second LED, a third cup (recess) having a third LED, and a fourth cup (recess) having a fourth LED, the lead frame including a respective cathode electrode for each cup and a respective anode electrode for each cup, each cup including an anode terminal connected to the anode electrode and a cathode terminal connected to the cathode electrode, the anode terminal and cathode terminal for each recess being disposed opposite each other on opposite edges of the housing.

[0058] At least one of the first LED, the second LED, and the third LED may comprise a chip-scale package.

[0059] According to another aspect, the present invention provides a lighting apparatus comprising a substrate (circuit board) and a plurality of lighting devices as defined herein mounted on the substrate. The lighting apparatus may be a linear lighting apparatus. The substrate may comprise a flexible circuit board.

[0060] These and other aspects and features of the present invention will become apparent to those of ordinary skill in the art upon review of the specific embodiments of the invention in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0061] [Figure 1] 1A and 1B are schematic representations of a known tunable surface mounted multi-LED package lighting device, with FIG. 1A showing a top view and FIG. 1B showing a cross-sectional side view taken along line AA. [Figure 2] 2 is a schematic cross-sectional side view of a packaged single-layer red light-emitting device according to one embodiment of the present invention. [Figure 3] 2 is a schematic cross-sectional side view of a packaged single-layer red light-emitting device according to one embodiment of the present invention. [Figure 4] 1 is a schematic cross-sectional side view of a packaged dual-layer red light-emitting device according to one embodiment of the present invention. [Figure 5] 1 is a schematic cross-sectional side view of a packaged dual-layer red light-emitting device according to one embodiment of the present invention. [Figure 6] 1 is a schematic cross-sectional side view of a CSP (chip-scale packaged) bi-layer red light-emitting device according to one embodiment of the present invention. [Figure 7] 1 is a schematic cross-sectional side view of a CSP (chip-scale packaged) bi-layer red light-emitting device according to one embodiment of the present invention. [Figure 8] FIG. 1 is a CIE 1931 chromaticity diagram illustrating the calculated color purity and dominant wavelength of light of a given chromaticity (color). [Figure 9]9A and 9B show measured spectra, i.e., intensity (arbitrary units) versus wavelength (nm), for (i) a comparative example Com.1 of a packaged red light-emitting device containing a broadband red phosphor (thick solid line), (ii) a comparative example Com.2 of a packaged red light-emitting device containing a narrowband red fluoride phosphor (thin solid line), (iii) a packaged single-layer red light-emitting device Dev.1 according to one embodiment of the present invention (dashed line), and (iv) a packaged two-layer red light-emitting device Dev.2 according to one embodiment of the present invention (dotted line). FIG. 9A shows the spectrum in the wavelength range from 550 nm to 700 nm (i.e., the green to red region), and FIG. 9B shows the spectrum in the wavelength range from 400 nm to 600 nm (i.e., the blue-violet to yellow region). FIG. 9C is a CIE 1931 chromaticity diagram illustrating the chromaticity (color), blackbody locus, and chromaticity gamut boundaries (solid lines) of light generated by (i) comparative packaged red light-emitting device Com.1 (solid circle), (ii) comparative packaged red light-emitting device Com.2 (cross), (iii) packaged single-layer red light-emitting device Dev.1 (solid triangle), and (iv) packaged double-layer red light-emitting device Dev.2 (solid diamond). [Figure 10] Figure 10A is a schematic plan view of a color-tunable multi-LED package lighting device utilizing a CSP (chip-scale packaged) bilayer red light-emitting device according to one embodiment of the present invention, and Figure 10B is a CIE 1931 chromaticity diagram illustrating the gamut of light that the color-tunable multi-LED package lighting device of Figure 10A can generate. [Figure 11] FIG. 1 is a schematic plan view of a color-tunable multi-LED package lighting device utilizing a CSP (chip-scale packaged) bi-layer red light-emitting device according to one embodiment of the present invention. [Figure 12] FIG. 1 is a schematic plan view of a color-tunable multi-LED package lighting device utilizing packaged red light-emitting devices according to one embodiment of the present invention. [Figure 13]13A-13C are schematic representations of a color-tunable multi-LED package lighting device comprising a PC red LED, a green LED, a blue LED, and a white LED according to one embodiment of the present invention, where FIG. 13A shows a top view, FIG. 13B shows a side cross-sectional view taken along line AA, and FIG. 13C shows a side cross-sectional view taken along line BB. FIG. 13D is a CIE 1931 chromaticity diagram illustrating the gamut of light that the color-tunable multi-LED package lighting device of FIGS. 13A-13C can generate. [Figure 14] 14A-14C are schematic representations of a color-tunable multi-LED package lighting device comprising a CSP PC red LED, a CSP PC green LED, a blue LED flip chip, and a CSP white LED, according to one embodiment of the present invention, where FIG. 14A shows a top view, FIG. 14B shows a side cross-sectional view taken along line AA, and FIG. 14C shows a side cross-sectional view taken along line BB. FIG. 14D-14F are schematic representations of a color-tunable multi-LED COB (chip-on-board) lighting device 1450 comprising a CSP PC red LED, a CSP PC green LED, a blue LED flip chip, and a CSP white LED, according to one embodiment of the present invention, where FIG. 14D shows a top view, FIG. 14E shows a side cross-sectional view taken along line CC, and FIG. 14F shows a side cross-sectional view taken along line DD. [Figure 15] Figure 15A is a schematic top view of a color-tunable multi-LED package lighting device comprising a PC red LED, a PC green LED, and two PC cool white (CW) LEDs according to one embodiment of the present invention, and Figure 15B is a CIE 1931 chromaticity diagram illustrating the gamut of light that the color-tunable multi-LED package lighting device of Figure 15A can generate. [Figure 16] 1 is a schematic representation of a color-tunable linear lighting fixture according to one embodiment of the present invention. [Figure 17]17A-17C are measured characteristics of a color-tunable multi-LED package lighting device (Pack 1) comprising a PC red LED (red), a PC green LED (green), a blue LED (blue), and a white LED (white). FIG. 17A shows the spectra, i.e., normalized intensity (arbitrary units) versus wavelength (nm), for the PC red LED (thick solid line), the PC green LED (dash-dotted line), the blue LED (dotted line), and the white LED (dashed line). FIG. 17B is a CIE 1931 chromaticity diagram illustrating the chromaticity (color) produced by the PC red LED (square), the PC green LED (diamond), the blue LED (triangle), and the white LED (cross), the ANSI CCT center point (solid circle), the device color gamut (solid line), and the blackbody locus (dashed line). FIG. 17C is a CIE 1931 chromaticity diagram illustrating the calculated color purity of the light produced by the PC red LED, the green LED, the blue LED, and the white LED. [Figure 18]18A-18C are graphs illustrating the measured emission characteristics of a color-tunable multi-LED package lighting device (Pack 1) operable to generate light with a nominal CCT from 2700K to 6500K and a CRI Ra of 90; FIG. 18A illustrates the spectrum, i.e., normalized emission intensity (arbitrary units) versus wavelength (nm), for a CCT of 2700K (dotted line), a CCT of 3000K (dashed line), and a CCT of 4000K; and FIG. 18B illustrates the spectrum, i.e., normalized emission intensity (arbitrary units) versus wavelength (nm), for a CCT of 5000K (dashed line). FIG. 18C is a CIE 1931 chromaticity diagram illustrating the chromaticity (color) of light produced by the color-tunable multi-LED package lighting device (Pack 1) for nominal CCTs of 2700K, 3000K, 4000K, 5000K, 5700K, and 6500K, and illustrating the emission locus (solid line), blackbody locus (dashed line), and MacAdam ellipse (SCDM—standard deviation of color matching) for CCTs from 2700K to 6500K. FIG. 18D is a CIE 1931 chromaticity diagram illustrating the color points produced by a color-tunable multi-LED package lighting device (Pack 1) operable to produce light having a CRI Ra of 95 for nominal CCTs of 2700K, 3000K, 4000K, 5000K, 5700K, and 6500K, the emission locus (solid line), the blackbody locus (dashed line), and the MacAdam ellipse for CCTs from 2700K to 6500K. [Figure 19]19A and 19B are measured optical characteristics of the color-tunable multi-LED package lighting device (pack 2), where FIG. 19A is a CIE 1931 chromaticity diagram illustrating the chromaticity (color points) of light generated by a PC red LED (square), a PC green LED (diamond), a blue LED (triangle), and a white LED (cross), the ANSI CCT center points (solid circles), the color gamut of the device (solid line), and the blackbody locus (dashed line), and FIG. 19B is a chromaticity diagram illustrating the color points of light generated by a color-tunable multi-LED package lighting device (pack 2) operable to generate light having a CRI Ra of 90 for nominal CCTs of 2700K, 3000K, 3500K, 4000K, 5000K, 5700K, and 6500K, the emission locus (solid line), the blackbody locus (dashed line), and the MacAdam ellipse for CCTs from 2700K to 6500K. [Figure 20] 20A-20D are schematic representations of a multi-LED multi-cavity package according to one embodiment of the present invention having a common cathode terminal configuration, where FIG. 20A shows a top view, FIG. 20B shows a cross-sectional side view taken along line AA, FIG. 20C shows a cross-sectional side view taken along line BB, and FIG. 20D shows a top view of a lead frame of the multi-LED package. [Figure 21] 21A-21D are schematic representations of a multi-LED, i.e., four-LED package according to one embodiment of the present invention, with each LED having a pair of anode and cathode electrical terminals, where FIG. 21A shows a top view, FIG. 21B shows a cross-sectional side view taken along line AA, FIG. 21C shows a cross-sectional side view taken along line BB, and FIG. 21D is a plan view of the lead frame of the multi-LED package. [Figure 22] 22A and 22B are schematic representations of a multi-LED (4 LED) package according to another embodiment of the present invention, with FIG. 22A showing a top view and FIG. 22B showing a top view of a lead frame of the multi-LED package. DETAILED DESCRIPTION OF THE INVENTION

[0062] Detailed Description of the Invention Package PC red LED In embodiments, particles of broadband red phosphor and narrowband red fluoride phosphor can be provided as a single layer and / or a mixture within the same layer, and because such devices comprise only one photoluminescent layer, these devices are referred to as "single layer" structure photoluminescent devices.

[0063] In other embodiments, the broadband red phosphor and the narrowband red fluoride phosphor can be included in respective layers, with the layer containing the narrowband red fluoride phosphor being located closer to the LED chip than the layer containing the broadband red phosphor. Because such devices comprise two photoluminescent layers, they are referred to as "two-layer" photoluminescent devices.

[0064] Single-layer PC package red LED A packaged single layer red light emitting device (PC red LED) 210 according to one embodiment of the present invention will now be described with reference to Figure 2, which shows a schematic cross-sectional side view of device 210. Light emitting device 210 may comprise a surface mounted device (SMD), such as a 2835 LED package, as shown.

[0065] Light-emitting device 210 includes a package 212 with a lead frame on which a housing 218 is molded. The lead frame includes an anode region 214 and a cathode region 216. Housing 214 includes a bottom 218A and a sidewall portion 218B, with sidewall portion 218B extending upward from opposite edges of bottom 218A. The inner surfaces of sidewall portion 218B slope inwardly relative to their respective vertical axes toward the bottom, and together with the inner surface (base) of bottom 218A, define a cavity (cup, recess) 220 in the shape of an inverted pyramid or inverted cone.

[0066] A portion of the leadframe anode region 214 and a portion of the leadframe cathode region 216 extend laterally outside the edges of the housing 218 to form anode electrical terminals 222 and cathode electrical terminals 224, respectively, along opposite edges of the package 212, enabling electrical power to the anode (A) and cathode (C) of each LED chip.

[0067] The cavity (cup) 220 contains one or more InGaN-based LED chips (violet to blue LED chips), which are mounted on the bottom surface (inner surface) of the cavity 220. As shown, the LED chips 226 can be electrically connected to the lead frame 214 by bond wires 228. The device 210 can include three InGaN-based LED chips and can have a rated drive condition of 100 mA and 9 V.

[0068] The cavity (cup) 220 is filled with a red-emitting photoluminescent material 230, which forms a single-layer photoluminescent structure. The photoluminescent material layer 230 may include a light-transmitting (transparent) encapsulant, such as a silicone material, in which the red-emitting photoluminescent material 230 is dispersed.

[0069] In accordance with the present invention, the red photoluminescent material 230 includes a combination of a narrow-band red fluoride phosphor and a red phosphor, such as a broad-band red phosphor, that has an absorption efficiency higher than that of the narrow-band red fluoride phosphor. Details of suitable narrow-band and broad-band red phosphors are provided below. The photoluminescent layer 230 can contain materials other than the photoluminescent (phosphor) material, such as light-scattering particles or light-diffusing materials.

[0070] The single layer device 210 can be fabricated by dispersing a curable, light-transmitting liquid material, such as silicone, containing a mixture of narrowband red fluoride phosphor and broadband red phosphor and filling the cavity (cup) 220.

[0071] 3, there is shown a packaged single layer red light emitting device 310 formed in accordance with another embodiment of the present invention. This embodiment differs from FIG. 2 only in that the LED chip 326 comprises an LED flip chip.

[0072] Double-layer PC package Red LED A packaged bilayer red light emitting device (PC red LED) 410 according to one embodiment of the present invention will now be described with reference to FIG. 4, which shows a schematic cross-sectional view of the device 410.

[0073] 2 in that the photoluminescent material layer 430 is formed as a two-layer photoluminescent structure comprising a first photoluminescent layer 430A and a second photoluminescent layer 430B. The first photoluminescent layer 430A is closer to the LED chip 426 than the second photoluminescent layer 430B; i.e., the first photoluminescent layer 430A is closer to the LED chip 426 (i.e., is the proximal layer), while the second photoluminescent material layer 430B is further from the LED chip 426 (i.e., is the distal layer).

[0074] In terms of photoluminescent (phosphor) material, the first photoluminescent layer 430A contains only or substantially (at least 90% by weight) only narrow-band red fluoride phosphor. More specifically, in an embodiment, the first photoluminescent layer 430A contains K2SiF6:Mn 4+ The first photoluminescent layer 430A contains only K2SiF6:Mn (KSF) and no other photoluminescent materials. However, other materials, such as light diffusing (scattering) materials, can be added to the first photoluminescent layer 430A, although the amount of other materials is generally no more than 30% by weight of the narrow-band red fluoride phosphor. Furthermore, in this embodiment, the first photoluminescent layer 430A is made of K2SiF6:Mn dispersed in dimethylsilicone. 4+The first photoluminescent layer 430A is immediately adjacent to the LED chip 426 and may be in direct contact with the LED chip 426 as shown in Figure 4. There are no other photoluminescent materials or photoluminescent material-containing layers between the first photoluminescent layer 430A and the LED chip 426.

[0075] The second photoluminescent layer 430B contains a broadband red phosphor and is dispersed over the first photoluminescent layer 430A to fill the cavity (cup) 420.

[0076] Compared to the single-layer device 210 shown in FIG. 2, the narrow-band red fluoride phosphor and broad-band red phosphor in the single-layer light-emitting device are equally exposed to excitation light, e.g., blue excitation light, because they are located in the same position (within a layer) relative to the LED chip. Because the narrow-band red fluoride phosphor has a much lower blue absorption efficiency than the broad-band red phosphor, a larger amount of narrow-band red fluoride phosphor is required to convert sufficient blue light into the red emission required to be attributed to the narrow-band red fluoride phosphor. In contrast, in the two-layer light-emitting device 410, the narrow-band red fluoride phosphors in separate, individual layers 430A are individually exposed to blue excitation light; therefore, a larger proportion of the blue excitation light from the blue LED chip 426 can be absorbed by the narrow-band red phosphor, and the remaining blue excitation light can penetrate the photoluminescent layer 430B containing the broad-band red phosphor. In the two-layer photoluminescent structure, the first photoluminescent layer 430A can more effectively convert blue excitation light into narrow-band red light, and the amount / usage of the narrow-band red fluoride phosphor can be significantly reduced (up to about 40%) compared to the single-layer photoluminescent configuration (FIG. 2). An additional advantage of the two-layer photoluminescent structure is that the second photoluminescent layer 430B completely covers the first photoluminescent layer 430A, which effectively isolates the narrow-band red fluoride phosphor contained in the first photoluminescent layer 430A from direct contact with water / moisture in the ambient environment. Such a two-layer structure provides an effective solution to address the poor moisture resistance of narrow-band red fluoride phosphors.

[0077] 5, there is shown a packaged bi-layer light emitting device 510 formed in accordance with another embodiment of the present invention. This embodiment differs from FIG. 4 only in that the LED chip 526 comprises an LED flip chip.

[0078] CSP (Chip Scale Package) PC Red LED Although the above embodiments have been described with respect to packaged PC red LED devices, embodiments of the present invention find utility in chip-scale packaged light emitting devices. As used herein, a CSP configuration refers to a chip-scale packaging configuration that does not include a lead frame. In a CSP configuration, the LED chip may comprise an integrated component of the package. For example, one or more layers of material may be applied directly to the surface of a flip chip to form a packaged device. A particular advantage of the CSP configuration is the small size of the packaged device, which is comparable to the chip size.

[0079] FIG. 6 shows a side view of a CSP two-layer red light-emitting device 610 according to an embodiment of the present invention. In this embodiment, a first photoluminescent layer 630A containing a narrow-band red fluoride phosphor is applied as a uniform-thickness layer directly onto and covers at least the primary light-emitting surface (the top surface shown) of an LED flip chip 626. A second photoluminescent material layer 630B containing a broad-band red phosphor is applied or deposited (fabricated) as a uniform-thickness layer onto and covers the first photoluminescent layer 630A. As shown, the device 610 can further include a light-reflecting layer 632, such as white silicone or epoxy, covering the four sides of the LED chip to prevent excitation light from emitting from these sides. In other embodiments, the light-reflecting layer can cover the edges of the first and second photoluminescent layers to prevent excitation light from emitting from these edges.

[0080] 7 shows a side view of a CSP two-layer red light-emitting device 710 according to an embodiment of the present invention. In this embodiment, a first photoluminescent layer 730A containing a narrowband red fluoride phosphor is applied or deposited (fabricated) as a layer of uniform thickness directly onto at least the primary light-emitting surface (the top surface shown) and four side light-emitting surfaces of an LED flip chip 726, covering these surfaces. A second photoluminescent layer 730B containing a broadband red phosphor is applied or deposited (fabricated) as a layer of uniform thickness onto the top and side surfaces of the first photoluminescent layer 730A, covering these surfaces. The first and second photoluminescent layers 730A, 730B can be in the form of conformal coatings.

[0081] Narrowband red fluoride phosphor As used herein, narrow-band red phosphor refers to a photoluminescent material that, upon stimulation with excitation light, emits red light having a full width at half maximum (FWHM) emission intensity of about 5 nm to about 20 nm. As described herein, the narrow-band red phosphor is a manganese-activated potassium hexafluorosilicate phosphor (KSF) - K2SiF6:Mn, having a peak emission wavelength of about 631-632 nm. 4+ Other manganese-activated fluoride narrow-band red phosphors include manganese-activated potassium hexafluorogermanate phosphor (KGF) - K2GeF6:Mn 4+ and manganese-activated potassium hexafluorotitanate phosphor (KTF) - K2TiF6:Mn 4+ may include:

[0082] broadband red phosphor As used herein, a broadband red phosphor refers to a photoluminescent material that generates red light having a full width at half maximum (FWHM) emission intensity from about 50 nm to about 120 nm in response to stimulation by excitation light. As described above, the broadband red phosphor can include a rare earth-activated broadband red phosphor, which can be excited by blue light and, in response to this excitation, emits light having a peak emission wavelength λ within the range from about 620 nm to about 640 nm, that is, within the red region of the visible spectrum. p The rare earth-activated red photoluminescent material can include, for example, a europium-activated silicon nitride-based phosphor, a Group IIA / IIB sulfur selenide-based phosphor, or a silicate-based phosphor. Examples of the broadband red phosphor are listed in Table 1.

[0083] In some embodiments, the europium-activated silicon nitride-based phosphor includes a calcium aluminum silicon nitride phosphor (CASN: Calcium Aluminum Silicon Nitride) of the general formula CaAlSiN3:Eu 2+ (1:1:1:3 nitride). The CASN phosphor can be doped with other elements such as strontium (Sr) to have the general formula (Sr,Ca)AlSiN3:Eu 2+ and can be made into.

[0084] Alternatively, the rare earth-activated red phosphor can include a nitride-based phosphor having a general composition (Sr,Ba)2Si5N8:Eu 2+ (2:5:8 nitride).

[0085] The rare earth-activated red phosphor can also include a Group IIA / IIB sulfur selenide-based phosphor. The first example of the Group IIA / IIB sulfur selenide-based phosphor material has a 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 this phosphor material is the CSS phosphor (CaSe 1-x S x: (Eu). The emission wavelength of the CSS phosphor can be adjusted from 600 nm to 650 nm by changing the S / Se ratio in the composition.

[0086] In some embodiments, the rare-earth activated red phosphor can include a silicate-based material with the general composition (Sr 1-x M x ) y Eu z SiO5, where 0 < x ≤ 0.5, 2.6 ≤ y ≤ 3.5, 0.001 ≤ z < 0.5, and M is one or more divalent metals selected from the group consisting of Ba, Mg, Ca, and Zn.

[0087] [Table 1]

[0088] Color purity and dominant wavelength Color purity, or chroma, provides a measure of how closely the hue of light of a given color (chromaticity) resembles the color of a spectrum corresponding to light of the dominant wavelength λ d . Color purity can have values from 0% to 100%. FIG. 8 is a CIE 1931 chromaticity diagram illustrating a method for calculating the color purity and dominant wavelength of light of a given chromaticity (color).

[0089] Referring to FIG. 8, the color point (chromaticity) of light of a given color is shown on the chromaticity diagram by the cross 834, and the "white standard illuminant" is shown at point ⑧36. The "white standard illuminant" used herein is of equal energy (flat spectrum) and has color space coordinates CIE (1 / 3, 1 / 3). The straight line 838 (dashed line) connecting the color points 834 and 836 of the chromaticity intersects the outer curve boundary (perimeter) of the CIE color space at two points. The intersection point 840 closer to the given color CIE (x, y) 834 is the dominant wavelength λ d of the color as the wavelength of the pure (pure) spectrum (monochromatic) color at this intersection point. The intersection point c on the opposite side within the color space corresponds to the complementary dominant wavelength λ c and the complementary dominant wavelength λ cWhen added in the proper proportion to a given color, produces the color of a white standard illuminant.

[0090] The outer curved boundary of the chromaticity diagram is the monochromatic (spectral) locus, labeled with numbers indicating wavelengths in nanometers (nm). Monochromatic light (i.e., lying on the spectral locus) has a color purity of 100, while the color purity of the "white standard illuminant" 834 is 0. The color purity of light with chromaticity coordinates CIE(x, y) plotted on the chromaticity diagram is the difference between the "white standard illuminant" 836 and the dominant wavelength λ d is the ratio of the distance from the "white standard illuminant" 836 to the color point 834 to the distance to the intersection point 840 corresponding to

[0091] Experimental Test Data The following nomenclature is used herein to refer to PC red light-emitting devices: Com.# refers to a comparative PC red light-emitting device comprising a single red phosphor (i.e., a broadband red phosphor or a narrowband red fluoride phosphor), and Dev.# refers to a light-emitting device according to the present invention comprising a combination of a narrowband red fluoride phosphor and a broadband red phosphor.

[0092] The comparative PC red light-emitting device (Com.#) and the PC red light-emitting device according to the present invention (Dev.#) are comprised of SMD2835 package devices containing four blue LED chips connected in series. Each device is nominally 1.2 W (rated drive conditions are 100 mA and a forward drive voltage V of 12 V). f (It is).

[0093] The red phosphor used in the test device was KSF (K2SiF6:Mn 4+ ) narrowband red fluoride phosphor and CASN(Ca 1-x Sr x AlSiN3:Eu) broadband red phosphor.

[0094] For the comparative device, Com.# red phosphor (KSF or CASN) was contained in phenyl silicone and the mixture dispensed into the 2835 package filled the cavity of the LED.

[0095] For the single layer device (Dev.1): a mixture of KSF and CASN phosphors is contained in phenylsilicone and dispensed into a 2835 package to fill the cavity of the LED.

[0096] For the two-layer device (Dev.2): KSF phosphor is contained in phenyl silicone and dispensed into a 2835 package to partially fill the LED cavity. The KSF phosphor layer is cured in an oven. CASN phosphor is mixed with phenyl silicone and then dispensed onto the KSF to completely fill the LED cavity and then cured in an oven.

[0097] optical performance The test method involves measuring the total luminance of a PC red light emitting device in an integrating sphere.

[0098] Table 2 lists the compositions of the comparative devices Com.1 and Com.2 and the inventive devices Dev.1 and Dev.2. CASN 630, CASN 650, and CASN 655 refer to CASN phosphors with peak emission wavelengths of 630 nm, 650 nm, and 655 nm, respectively. The weight percentages in Table 2 are the weight percentages of the total phosphor weight. The weight values in Table 2 are the weight of the KSF phosphor normalized to the weight of the KSF phosphor in the comparative PC red LED Com.2.

[0099] As can be seen from Table 2, with regard to the phosphor composition: Com.1 comprises a single-layer phosphor structure containing 100% by weight of CASN 630; Com.2 comprises a single-layer phosphor structure containing 100% by weight of KSF; Dev.1 comprises a single-layer phosphor structure containing a combination of 67% by weight of KSF and 33% by weight of CASN 650; and Dev.2 comprises a two-layer phosphor structure having a first phosphor layer containing 61% by weight of KSF and a second phosphor layer containing 39% by weight of CASN 655.

[0100] [Table 2]

[0101] Table 3 lists the measured optical performance of PC red light-emitting devices (PC red LEDs) Com.1, Com.2, Dev.1, and Dev.2. Figures 9A and 9B show the measured spectra, i.e., intensity (arbitrary units) versus wavelength (nm), for (i) a comparative packaged red light-emitting device Com.1 containing a broadband red phosphor (thick solid line), (ii) a comparative packaged red light-emitting device Com.2 containing a narrowband red fluoride phosphor (thin solid line), (iii) a packaged single-layer red light-emitting device Dev.1 according to one embodiment of the present invention (dashed line), and (iv) a packaged double-layer red light-emitting device Dev.2 according to one embodiment of the present invention. Figure 9A shows the wavelength portion of the spectrum from 550 nm to 700 nm (i.e., the green-red region). Figure 9B shows the wavelength portion of the spectrum from 400 nm to 600 nm (i.e., the blue-violet-yellow region), illustrating "blue light pass." FIG. 9C is a CIE 1931 chromaticity diagram illustrating the chromaticity (color) of light generated by (i) comparative packaged red light-emitting device Com.1 (solid circle), (ii) comparative packaged red light-emitting device Com.2 (cross), (iii) packaged single-layer red light-emitting device Dev.1 (solid triangle), and (iv) packaged double-layer red light-emitting device Dev.2 (solid diamond), the blackbody locus (dashed line), and the boundaries of the chromaticity gamut (solid line).

[0102] [Table 3]

[0103] As can be seen from Table 3, the comparative device Com.1, which contains only a broadband red phosphor (CASN 630), has a peak emission wavelength λ of 639 nm. p 7.29lm (100%) luminous flux and 10.0lm / W luminous efficacy, FWHM of 67nm, dominant wavelength λ of 620nm d , and produces red light with a color purity of 99.7%. In comparison, the comparative device Com.2, which contains only narrow-band red fluoride phosphor (KSF), produces a peak emission wavelength λ of 633 nm. pIncreased luminous flux of 13.89 lm (190%) and luminous efficacy of 11.5 lm / W, FWHM of 7 nm, dominant wavelength λ of 627 nm d , and produces red light with 87.3% color purity. Note that, as might be expected, the use of the narrowband red fluoride phosphor (Com.2) results in a significant (90%) increase in lumen output / efficacy, a reduction in FWHM (from 67 nm to 7 nm), and a decrease in color purity (87.3% compared to 99.7%) compared to the use of the broadband red phosphor (Com.1).

[0104] Note that, referring to FIG. 9B, for Com.1, there is no evidence of blue-violet / blue light (400-500 nm) in the final emission spectrum (thick solid line), indicating that all of the blue light generated by the LED is converted to red light; i.e., there is no evidence of "blue light pass" in the luminescence generated by the Com.1 device. In contrast, for Com.2, the emission spectrum (thin solid line) shows a clear peak at 944 (λ p The wavelength (approximately 435 nm) of Com.2 is in the blue-violet / blue region of the spectrum, with peak 944 resulting from unconverted blue light generated by the LED, known as "blue light pass." The significant decrease in color purity of the red light produced by Com.2 compared to Com.1 (87.3% compared to 99.7%) is due to the unconverted blue light 944, which decreases the chromaticity (CIE x) of the light and shifts the chromaticity (color point 834—Figure 8) further away from the curve boundary of the chromaticity diagram, thereby reducing color purity. Increasing the weight loading of narrow-band red fluoride phosphor (KSF) relative to the binder (silicone) from 70% to 80% only increases the color purity of the light produced by Com.2 to a value of 95%. Therefore, a significant increase in KSF loading alone significantly increases the cost of manufacturing without significantly increasing the device's light performance / purity. Therefore, the combination of a narrow-band red fluoride phosphor (eg, a manganese-activated fluoride narrow-band red phosphor) with a red phosphor having a higher absorption efficiency, such as a broad-band red phosphor, is advantageous.

[0105] As can be seen from Table 3, the single layer device Dev. 1, which contains a combination of a narrowband red fluoride phosphor and a broadband red phosphor (CASN 650), has a peak emission wavelength λ of 633 nm. p 14.89lm (204%) and 12.3lm / W luminous efficacy, 27nm FWHM, 619nm dominant wavelength λ d , and produces red light with a color purity of 94.2%. Referring to FIG. 9B, Dev. 1 produces a peak 946 (λ ) in the blue-violet / blue region of the spectrum. p The Dev.1 light has a wavelength of approximately 445 nm, with peak 946 resulting from unconverted blue light, or "blue light pass," although the intensity of peak 946 is much smaller (approximately half) than peak 944 of Com.2. The increase in color purity of the red light produced by Dev.1 compared to Com.2 (94.2% compared to 87.3%) is due to the reduction in unconverted blue light in the final luminescence product. As shown in FIG. 9C , the reduction in unconverted blue light increases the chromaticity CIE x value of the light produced by Dev.1 (934a—solid triangle) compared to Com.2 (cross), shifting the chromaticity point of the light toward the chromaticity gamut boundary curve (solid line) on the chromaticity diagram, thereby increasing color purity. The increase in color purity of the light produced by Dev.1 compared to Com.2 is due to the inclusion of a broadband red phosphor, which reduces the intensity of unconverted blue light 946 in the final luminescence product. As can be seen from Table 2, the inclusion of the broadband red phosphor also reduces the amount (weight) of narrowband red fluoride phosphor used (34% weight reduction compared to Com.2).

[0106] As can be seen from Table 3, the bilayer device Dev. 2, which contains a combination of a narrowband red fluoride phosphor and a broadband red phosphor (CASN 650), has a peak emission wavelength λ of 632 nm. p 17.72lm (243%) luminous flux and 14.5lm / W luminous efficacy, 7.49nm FWHM, 621nm dominant wavelength λ d , and produces red light with a color purity of 97.7%. Referring to FIG. 9B, Dev. 2 produces a peak 948 (λ ) in the blue-violet / blue region of the spectrum. p445 nm), with peak 948 resulting from unconverted blue light—"blue light pass"—but peak 948 is broadened and much less intense (about one-fourth the intensity) than peak 944 of Com.2. The increase in color purity of the red light produced by bilayer device Dev.2 compared to single-layer device Dev.1 (97.7% compared to 94.2%) is due to the reduction in unconverted blue light 948 in the final luminescent product. As shown in FIG. 9C , the reduction in unconverted blue light increases the chromaticity CIE x value of the light produced by Dev.2 (934b—diamonds) compared to Dev.1 (934a—triangles), shifting the light's chromaticity point 934b toward the chromaticity gamut boundary curve (solid line) on the chromaticity diagram, thereby increasing color purity. The reduction in "blue light transmission" is due to the two-layer photoluminescence structure, in which the narrow-band red fluoride phosphor is provided in a separate layer adjacent to the LED chip. This configuration effectively increases the absorption efficiency of the narrow-band red fluoride phosphor because it does not compete with the broad-band red phosphor for blue photons, as is the case in the single-layer photoluminescence structure. Furthermore, as can be seen in Table 3, the two-layer photoluminescence structure can reduce the amount (weight) of narrow-band red fluoride phosphor used (40% weight reduction compared to Com. 2) while increasing color purity and intensity / luminous efficiency (243% compared to 204%).

[0107] In summary, it has been found that red light-emitting devices according to embodiments of the present invention, including a combination of a narrow-band red fluoride phosphor and a broad-band red phosphor, can provide numerous advantages, including, but not limited to: (1) a significant reduction (approximately 40%) in the amount of narrow-band red fluoride phosphor used; (2) a significant reduction, or even elimination, of "blue light pass," which results in an increase in the color purity of the red light generated by the device; (3) a significant increase in the light intensity / luminous efficacy of the device; and (4) color purity that is comparable to or exceeds that of a PC red LED that utilizes only a broad-band red phosphor.

[0108] Color-tunable multi-LED lighting device Phosphor-converted red LEDs (PC red LEDs) according to embodiments of the present invention find utility as red light sources in light-emitting devices, such as, for example, RGB (red, green, blue) multi-LED lighting devices comprising a red LED, a green LED, and a blue LED. As described herein, PC red LEDs can be configured as packaged devices or CSP (chip-scale packaged) devices with single-layer or double-layer photoluminescent structures. Green LEDs can be configured as packaged or CSP (chip-scale packaged) phosphor-converted LEDs (PC green LEDs) with single-layer photoluminescent structures comprising a green photoluminescent material (phosphor) covering a blue-violet to blue LED chip. The green phosphor can be, for example, a green silicate phosphor (Sr 1-x Ba x )2SiO4:Eu), β-SiAlON phosphor, or green-emitting YAG (Yttrium Aluminum Garnet) phosphor ((Y, Ba) 1-x (Al 1-y Ga y )5O 12 :Ce x Alternatively, the green LED may comprise a direct-emitting green LED chip (e.g., an InGaN-based LED chip). The blue LED typically comprises an InGaN-based LED chip or a flip-chip. The red, green, and blue LEDs may be housed in a package, such as a surface-mount package. When the red LED comprises a PC-red LED and the green LED comprises a PC-green LED or a direct-emitting green LED, the red, green, and blue LEDs may be mounted on a substrate, such as a printed circuit board, in a so-called chip-on-board (COB) configuration.

[0109] FIG. 10A shows a schematic plan view of a color-tunable multi-LED package lighting device 1050 utilizing red light-emitting devices (PC red LEDs). The device 1050 includes a package (e.g., SMD) 1012 including a lead frame and a housing 1018 defining a single cavity (cup / recess) 1020 (e.g., circular as shown), which contains a PC red LED 1052, a green LED 1054, and a blue LED 1056. The PC red LED 1052 can be a PC red LED according to an embodiment of the invention, such as a single-layer or dual-layer CSP (chip-scale packaged) red light-emitting device, such as the CSP devices of FIG. 6 or FIG. 7. The green LED can be a CSP PC green LED with a broadband green phosphor coated over the LED flip chip. The green LED 1054 can be a CSP PC green LED with a broadband green phosphor coated over the LED flip chip. The green phosphor generates light having a peak emission wavelength between 500 nm and 565 nm. Alternatively, the green LED can comprise a direct-emitting green LED chip (e.g., an InGaN-based LED chip). The blue LED 1056 typically comprises an InGaN-based LED chip and generates light having a dominant wavelength between 430 nm and 480 nm. The cavity (cup) 1020 can be filled with an optically transmissive medium (e.g., silicone) to provide environmental protection for the red LED 1052, green LED 1054, and blue LED 1056. As shown, the package 1012 typically includes respective anode and cathode electrical terminals 1022, 1024, allowing electrical power to be individually supplied to the anode and cathode of each of the red (R), green (B), and blue LEDs 1010, 1054, 1056.

[0110] Light-emitting device 1050 can emit light of colors ranging from blue to red, as well as light of different color temperatures. FIG. 10B is a CIE 1931 chromaticity diagram illustrating the gamut (color / color temperature) of light that light-emitting device 1050 can emit. This CIE chromaticity diagram shows chromaticity (color point) 1057R of red light emitted by a PC red LED, chromaticity (color point) 1057G of green light emitted by a PC green LED, and chromaticity (color point) 1057B of blue light emitted by a blue LED. A line 1058 connecting points 1058R, 1057G, and 1057B defines a triangle representing the chromaticity (color) / color temperature gamut of light that light-emitting device 1050 can emit—i.e., the device can emit light of any color / color temperature within or on the boundary of this triangle. As can be seen from the chromaticity diagram, device 1050 is capable of producing light with color temperatures that lie on the blackbody locus (dashed line) and that correspond to ANSI CCT (American National Standards Institute Correlated Color Temperature) center points within or on the boundary of this triangle.

[0111] FIG. 11 shows a schematic plan view of a color-tunable multi-LED package lighting device 1150 utilizing a red light-emitting device (PC red LED) 1152. The device 1150 comprises a package 1112 having three cavities 1120a, 1120b, and 1120c, each containing a phosphor-converted red LED 1152, a green LED 1154, and a blue LED 1156. As shown, the PC red LED 1152 can be a PC red LED according to an embodiment of the invention, such as a single-layer or dual-layer CSP (chip-scale packaged) red light-emitting device, e.g., the CSP devices of FIG. 6 or FIG. 7. The green LED 1154 can be a CSP PC green LED or a direct-emitting green LED (e.g., an InGaN-based LED chip). The blue LED 1156 typically comprises an InGaN-based LED chip and generates light having a dominant wavelength between 430 nm and 480 nm. Each cavity 1120a, 1120b, 1120c can be filled with a light-transmitting medium (e.g., silicone) to provide environmental protection for the red LED 1152, green LED 1154, and blue LED 1156. As shown, the package 1112 generally includes respective anode electrical terminals 1122R, 1122G, 1122B and cathode electrical terminals 1124R, 1124G, 1124B to allow independent power supply to the anode and cathode of each of the red (R) LED 1152, green (G) LED 1154, and blue (B) LED 1156. Like the lighting device 1050 of FIG. 10, the lighting device 1150 can generate light in a blue-red color and at different color temperatures—i.e., light with color temperatures within or on the boundary of the triangle on the chromaticity diagram ( FIG. 10B ).

[0112] FIG. 12 shows a schematic plan view of a color-tunable multi-LED package lighting device 1250 utilizing a red light-emitting device (PC red LED) 1252. The light-emitting device 1250 includes a package 1212 having three cavities 1220a, 1220b, and 1220c, each containing a PC red LED 1252, a green LED 1254, and a blue LED chip 1256. As shown, the red LED 1252 can comprise a PC red LED according to an embodiment of the invention, such as a single-layer or dual-layer light-emitting device, such as the packaged devices of FIGS. 2-5, with cavity 1220a filled with a narrow-band red fluoride phosphor and a broad-band red phosphor. As shown, the green LED 1254 can comprise a PC green LED, such as the packaged device with cavity 1220b filled with a green phosphor. The blue LED typically comprises an InGaN-based LED chip and emits light having a dominant wavelength between 430 nm and 480 nm. The cavity 1220c can be filled with an optically transparent medium (e.g., silicone) to provide environmental protection for the blue LED 1256. As shown, the package 1212 typically includes respective anode electrical terminals 1222R, 1222G, and 1222B and cathode electrical terminals 1224R, 1224G, and 1224B, allowing power to be independently supplied to the anode and cathode of each of the red (R) LED 1210, green (G) LED 1254, and blue (B) LED 1256. Like the lighting device 1050 of FIG. 10, the lighting device 1250 can emit light ranging in color from blue to red, as well as light of different color temperatures—i.e., light with color temperatures within or on the boundary of the triangle on the chromaticity diagram (FIG. 10B).

[0113] 13A-13C are schematic representations of a color-tunable multi-LED package lighting device comprising PC red, green, blue, and white LEDs, according to one embodiment of the present invention, with FIG. 13A showing a top view, FIG. 13B showing a side cross-sectional view taken along line AA, and FIG. 13C showing a side cross-sectional view taken along line BB. The device 1350 comprises a package 1312, which comprises a lead frame (anode region 1314 and cathode region 1316) and a housing 1318 molded over the lead frame. The housing 1318 comprises a first cavity (cup) 1320a, a second cavity (cup) 1320b, a third cavity (cup) 1320c, and a fourth cavity (cup) 1320d, which contain a PC red LED 1352, a green LED 1354, a blue LED 1356, and a white LED 1359, respectively. As shown, the package 1312 comprises a first pair of anode and cathode electrical terminals 1322aR, 1324aR connected to the first cavity 1320a, a second pair of anode and cathode electrical terminals 1322bG, 1324bG connected to the second cavity 1320b, a third pair of anode and cathode electrical terminals 1322cB, 1324cB connected to the third cavity 1320c, and a fourth pair of anode and cathode electrical terminals 1322dW, 1324dW connected to the fourth cavity 1320d, allowing power to be supplied independently to each of the red (R) LED 1352, green (G) LED 1354, blue (B) LED 1356, and white (W) LED 1359.

[0114] As shown, the red LED 1352 can comprise a PC red LED according to an embodiment of the invention, such as a single-layer or dual-layer light-emitting device, e.g., the packaged device of FIGS. 2-5, where a first cavity 1320a contains a blue-violet-blue LED chip 1326, and the first cavity 1320a is filled with a photoluminescent layer of a narrow-band red fluoride phosphor and a broad-band red phosphor. As shown, the green LED 1354 can comprise a PC green LED, such as a packaged device, where a second cavity 1320b contains a blue-violet-blue LED chip 1326, and the second cavity 1320b is filled with a green phosphor photoluminescent layer 1360 that covers the blue-violet LED chip 1326. The blue LED 1356 comprises a blue LED chip that emits light having a dominant wavelength between 430 nm and 480 nm. The third cavity 1320c can be filled with a light-transmitting medium (e.g., silicone) to provide environmental protection for the blue LED chip 1356. As shown, the white LED 1359 can include a packaging device in which the fourth cavity 1320d contains the blue-violet-blue LED chip 1326, and the fourth cavity 1320d is filled with a green-red phosphor photoluminescent layer covering the blue-violet LED chip 1326. The white LED 1359 is configured to emit warm white (WW) light having a CCT (color temperature) of 2000K to 4000K.

[0115] The lighting device 1350 can generate light of colors (chromaticities) ranging from blue to red, as well as light of different color temperatures. Figure 13D is a CIE 1931 chromaticity diagram illustrating the gamut (color / color temperature) of light that the lighting device 1350 can generate. The CIE chromaticity diagram shows the chromaticity (color point) 1357R (solid diamond) of red light generated by a PC red LED, the chromaticity (color point) 1357G (solid diamond) of green light generated by a PC green LED, the chromaticity (color point) 1357B (solid diamond) of blue light generated by a blue LED, and the chromaticity (color point) 1357W (cross) of light generated by a white LED. Line 1358 connecting points 1357R, 1357G, and 1357B defines a triangle that represents the gamut of chromaticity (color) / color temperature of light that lighting device 1350 can generate—i.e., the device can generate light of any chromaticity (color) / color temperature that lies within or on the boundary of the triangle. Note that the white LED's color point 1357W lies within the triangle, so the white LED does not increase the color gamut of the device. However, the inclusion of the white LED simplifies the generation of light of other color temperatures by adding green / blue light to the light generated by the white LED, and the generation of light with a higher color rendering index (CRI) Ra by adding red light to the light generated by the white LED.

[0116] 14A-14C are schematic representations of a color-tunable multi-LED package lighting device including a CSP PC red LED, a CSP PC green LED, a blue LED flip chip, and a CSP white LED, according to one embodiment of the present invention, where FIG. 14A shows a top view, FIG. 14B shows a side cross-sectional view taken along line AA, and FIG. 14C shows a side cross-sectional view taken along line BB. Device 1450 is similar to device 1350 of FIG. 13 and includes a chip-scale packaged (CSP) LED. As shown, red LED 1452 is comprised of a CSP PC red LED according to an embodiment of the present invention, such as a single-layer or dual-layer red light-emitting device, e.g., the CSP devices of FIGS. 6 and 7, with a blue-violet LED flip chip 1426 having a photoluminescent layer 1430 of narrow-band red fluoride phosphor and broad-band red phosphor on at least the light-emitting surface of the LED flip chip. The first cavity 1420a can be filled with an optically transparent medium (e.g., silicone) to provide environmental protection for the CSP PC red LED 1452. As shown, the CSP PC green LED 1454 can include a violet-to-blue LED flip chip 1426 having a green phosphor photoluminescent layer 1460 on at least the light-emitting surface of the LED flip chip 1426. The second cavity 1420b can be filled with an optically transparent medium (e.g., silicone) to provide environmental protection for the CSP PC green LED 1454. The blue LED 1456 includes a blue LED chip that emits light having a dominant wavelength between 430 nm and 480 nm. The third cavity 1420c can be filled with an optically transparent medium (e.g., silicone) to provide environmental protection for the blue LED chip 1456. As shown, the CSP white LED 1459 can comprise a violet-blue LED flip chip 1426 having a green-red phosphor photoluminescent layer 1462 on at least the light emitting surface of the LED flip chip 1426.The fourth cavity 1420d can be filled with a light-transmitting medium (e.g., silicone) to provide environmental protection for the CSP white LED 1459. The white LED 1459 can be configured to emit warm white (WW) light with a CCT (color temperature) between 2000K and 5000K. The package 1414 generally comprises anode electrical terminals 1422aR, 1422bG, 1422cB, and 1422dW connected to each cavity 1420a, 1420b, 1520c, and 1420d, respectively, and cathode electrical terminals 1424a, 1424b, 1424c, and 1424d connected to each cavity 1420a, 1420b, 1520c, and 1420d, respectively, to enable power to be supplied to the anodes and cathodes of each of the red (R) LED 1452, green (G) LED 1454, blue (B) LED 1456, and white LED 1459. Like light emitting device 1250 of FIG. 12, light emitting device 1450 can emit light of colors ranging from blue to red, as well as light of different color temperatures—i.e., light of colors / color temperatures within or on the boundary of the triangle on the chromaticity diagram (FIG. 10B).

[0117] As described herein, when the LEDs (red, green, blue, and white) are configured as CSP LEDs (i.e., CSP PC red, CSP PC green, and CSP white LEDs) or direct-emitting (DE) LEDs (i.e., DE green and DE blue LEDs), the LEDs can be mounted on a substrate, such as a printed circuit board, resulting in a so-called chip-on-board (COB) packaging configuration. Figures 14D-14F are schematic representations of a color-tunable multi-LED COB lighting device comprising a CSP PC red LED, a CSP PC green LED, a blue LED flip-chip, and a CSP white LED according to one embodiment of the present invention. Figure 14D shows a top view, Figure 14E shows a side cross-sectional view taken along CC, and Figure 14F shows a side cross-sectional view taken along DD. The lighting device 1450 includes a substrate 1470, such as a printed circuit board, on which a CSP PC red LED 1452, a CSP PC green LED 1454, a blue LED flip chip 1456, and a CSP white LED 1459 are mounted on the same surface. As shown, the red LED 1452, green LED 1454, blue LED 1456, and white LED 1459 may be configured in a square array on the substrate. The red LED 1452 may be a CSP PC red LED according to an embodiment of the invention, such as a single-layer or dual-layer red light-emitting device like the CSP devices of FIGS. 6 and 7, which includes a blue-violet LED flip chip 1426 having a narrowband red fluoride layer and a broadband red phosphor photoluminescent layer 1430 on at least the light-emitting surface of the LED flip chip 1426. CSP PC 1454 can include a violet-blue LED flip chip 1426 having a green phosphor photoluminescent layer 1460 on at least the light emitting surface of the LED flip chip. Blue LED 1456 can include a blue LED flip chip that emits light having a dominant wavelength between 430 nm and 480 nm.The CSP white LED 1459 can include a violet-blue LED flip chip 1426 having a green-red phosphor photoluminescent layer 1462 on at least the light-emitting surface of the LED flip chip 1426. The white LED 1459 can be configured to emit warm white (WW) light with a CCT (color temperature) of 2000K to 5000K. As shown, the red LED 1452, the green LED 1454, and the white LED 1459 include a light-reflecting layer 1432, such as white silicone or epoxy, that covers the four sides of the LED chip 1426 to prevent excitation light from emitting from those sides. Like lighting device 1250 of FIG. 12, lighting device 1450 can generate light of colors ranging from blue to red, and can generate light of different color temperatures—i.e., colors / color temperatures within or on the boundary of a triangle on the chromaticity diagram (FIG. 10B).

[0118] 15A is a schematic top view of a color-tunable multi-LED package lighting device 1550 including a PC red LED, a PC green LED, and two cool white (CW) LEDs, according to one embodiment of the present invention. The lighting device 1550 includes a package 1512 including a lead frame and a housing 1518 molded onto the lead frame. The housing 1518 includes a first cavity 1520a, a second cavity 1520b, a third cavity 1520c, and a fourth cavity 1520d, which contain a PC red LED 1552, a PC green LED 1554, a first CW LED 1564, and a second CW LED 1564, respectively. As shown, the red LED 1552 can be a PC-red LED according to an embodiment of the invention, such as a single-layer or dual-layer red light-emitting device, such as the packaged devices of Figures 2-5, where a first cavity 1520a contains a blue-violet-blue LED chip 1526 and is filled with a narrow-band red fluoride phosphor and a broad-band red phosphor photoluminescent layer overlying the blue-violet-blue LED chip 1526. As shown, the green LED 1554 can be a PC-green LED, such as a packaged device, where a second cavity 1520b contains a blue-violet-blue LED chip 1526 and is filled with a green phosphor photoluminescent layer overlying the blue-violet-blue LED chip 1526. As shown, the first and second CW LEDs 1564 can comprise a packaged device in which the third and fourth cavities each contain a violet-blue LED chip 1526 filled with a green-yellow phosphor photoluminescent layer covering the violet-blue LED chip 1526. The first and second CW LEDs 1564 can be configured to generate white light with a CCT (color temperature) of 5000K to 8000K. The first and second CW LEDs 1564 can generate CW light of the same CCT or CW light of different CCTs.The package 1512 generally includes respective anode electrical terminals 1522aR, 1522bG, 1522cCW, and 1522dCW and cathode electrical terminals 1524aR, 1524bG, 1524cCW, and 1524dCW connected to each cavity, allowing power to be independently supplied to the anode and cathode of each of the red (R) LED 1552, green (G) LED 1554, and first and second CW LEDs 1564.

[0119] The lighting device 1550 can generate light of colors ranging from green to red, as well as light of different color temperatures. FIG. 15B is a CIE 1931 chromaticity diagram illustrating the gamut (color / color temperature) of light the lighting device 1550 can generate. The chromaticity diagram in FIG. 15B shows the chromaticity (color point) 1557R (solid diamond) of red light generated by a PC red LED, the chromaticity (color point) 1557G (solid diamond) of green light generated by a PC green LED, and the chromaticity (color point) 1557CW (solid diamond) of light generated by a CW LED. A line 1558 connecting points 1557R, 1557G, and 1557CW defines a triangle representing the gamut (color) / color temperature (chromaticity) of light the lighting device 1550 can generate—i.e., the device can generate light of any chromaticity (color) / color temperature within or on the boundary of the triangle. The inclusion of a CW LED can simplify the generation of light of other color temperatures by adding green / red light to the light generated by the CW LED.

[0120] FIG. 16 is a schematic top view of a color-tunable linear lighting device 1668 according to one embodiment of the present invention. The color-tunable linear lighting device 1668 comprises a linear (elongated) substrate 1670, such as a strip of a metal core printed circuit board (MCPCB) or a strip of a flexible circuit board, and a multi-LED lighting device 1650 mounted on and connected to the substrate. As shown, the color-tunable multi-LED lighting device 1650 can be arranged in a linear array along the elongated direction of the substrate. For illustrative purposes only, the color-tunable multi-LED lighting device 1650 is shown to comprise the device of FIGS. 13A-13C and includes a PC red LED (R), a green LED (G), a blue LED (B), and a white LED (W). It should be apparent that the lighting device 1650 can comprise other color-tunable multi-LED lighting devices described herein. Each LED of a given color may be electrically connected in series, with anode electrical connectors 1672R, 1672G, 1672B, and 1672W and cathode electrical connectors 1674R, 1674G, 1674B, and 1674W at opposite ends of the substrate for each string of LEDs.

[0121] Experimental Test Data Pack # is used herein to represent a color-tunable multi-LED lighting device (lighting device) according to the present invention.

[0122] A color-tunable multi-LED package lighting device, designated Pack 1, includes the device of FIGS. 13A-13C and includes a PC red LED, a PC green LED, a blue LED, and a PC white LED. The PC red LED in the first cavity has a single layer structure, which is made of KSF (K2SiF6:Mn 4+ ) narrowband red fluoride phosphor and CASN(Ca 1-x Sr xThe LED in the third cavity contains an InGaN blue LED chip. The white LED in the fourth cavity contains a single-layer PC white LED, which contains a green-to-red photoluminescent material (e.g., (Ba,Sr)2SiO4 and CASN). The red phosphors (KSF and CASN) are contained in a phenylsilicone mixture, and the mixture is dispensed into the first cavity of the package to completely cover the blue-violet-to-blue InGaN LED chip. The green LED in the second cavity contains a PC green LED, which contains a blue-violet-to-blue InGaN LED chip and a green silicate phosphor. The green phosphor ((Ba,Sr)2SiO4) is contained in a phenylsilicone mixture, and the mixture is dispensed into the second cavity of the package to cover the blue-violet-to-blue InGaN LED chip. The blue LED in the third cavity contains an InGaN blue LED chip. The white LED in the fourth cavity contains a single-layer PC white LED, which contains a green-to-red photoluminescent material (e.g., (Ba,Sr)2SiO4 and CASN). A green-red phosphor is contained in phenyl silicone, and this mixture is dispensed into the fourth cavity of the package to cover the blue-violet-blue InGaN LED chip.

[0123] The color-tunable multi-LED lighting device of the present invention includes four individual LEDs (red, green, blue, and white) driven by four independent currents. To generate white light of different CCTs, the light generated by the white LED can be combined with light from red, green, and / or blue LEDs in different ratios to generate light of any CIE white color point on the blackbody locus, preferably meeting ANSI lighting standards. In contrast, current smart lighting products use one cool white (CW) LED and one warm white (WW) LED and do not mix light from RGB LEDs. These smart lighting products can tune the CIE white color point along the line connecting the CIE CW color point to the CIE WW color point; for example, they can tune the CCT from 2700K (WW) to 6500K (CW). For CIE points between the CIE CW color point and the CIE WW color point, especially those midway between the CCT color points of approximately 4000 K, the CIE color points deviate significantly from the blackbody locus. As a result, current smart lighting products are unable to generate light with a CIE white color point that lies on the blackbody locus throughout their color temperature operating range, and struggle to meet ANSI lighting standards.

[0124] Table 4 lists the measured optical characteristics of the PC red LED (R), PC green LED (G), blue LED (B), and white LED (W) in Color-Tunable Multi-LED Package Lighting Device Pack 1. As can be seen from Table 4, the PC red LED has a dominant wavelength (λ d The PC green LED produces red light with a dominant wavelength of 547 nm and 90% color purity, the PC green LED produces light with a dominant wavelength of 547 nm and 80% color purity, and the blue LED produces light with a dominant wavelength of 467 nm and 99% color purity. The white LED produces warm white (WW) light with a CCT of 3000 K and an average color rendering index (CRI Ra) of 70. For comparison, the light produced by the white LED has a dominant wavelength of 585 nm and 52% color purity.

[0125] [Table 4]

[0126] 17A-17C are measured optical characteristics of a color-tunable multi-LED package lighting device (Pack 1), where FIG. 17A shows the spectra, i.e., normalized intensity (arbitrary units) versus wavelength (nm), for the PC red LED (thick solid line), PC green LED (dash-dotted line), blue LED (dotted line), and white LED (dashed line); FIG. 17B is a CIE 1931 chromaticity diagram illustrating the chromaticity (color points), ANSI CCT center points (solid circles), device color gamuts (solid lines), and blackbody locus (dashed lines) of the light emitted by the PC red LED (squares), PC green LED (diamonds), blue LED (triangles), and white LED (crosses); and FIG. 17C is a CIE 1931 chromaticity diagram illustrating the calculated color purity of the light emitted by the PC red LED, PC green LED, blue LED, and white LED.

[0127] Referring to Figure 17A, the PC red LED exhibits a low-intensity blue peak 1747 at approximately 449 nm, corresponding to a small amount of "blue light pass." The CIE chromaticity diagram in Figure 17B shows the chromaticity (color point) 1776 (square) of red light produced by the PC red LED, the chromaticity (color point) 1778 (diamond) of green light produced by the PC green LED, the chromaticity (color point) 1780 (triangle) of blue light produced by the blue LED, and the chromaticity (color point) 1782 (cross) of light produced by the white LED. The line 1784 connecting points 1776, 1778, and 1780 defines a triangle representing the color / color temperature (chromaticity) of light that the lighting device pack 1 can produce—i.e., the device can produce light of any color / color temperature on or within the triangle. Note that the lowest CCT on the blackbody locus (dashed line) of light that the device can generate is approximately 2240K, which corresponds to the intersection 1786 of the line 1784 connecting color points 1776 and 1778 with the blackbody locus.

[0128] The CIE chromaticity diagram in Figure 17C illustrates the calculated color purity of light produced by a PC red LED, a PC green LED, a blue LED, and a white LED. As explained herein, color purity, or saturation, is the degree to which the hue of light of a given color (chromaticity) is at a dominant wavelength λ.d The chromaticity (color points) 1776, 1778, 1780, and 1782 of the PC red LED, PC green LED, blue LED, and white LED are indicated on a chromaticity diagram by crosses, and the "white standard illuminant," CIE (1 / 3, 1 / 3), is indicated by point 1736. Respective lines 1738R, 1738G, 1738B, and 1738W connecting each color point 1776, 1778, 1780, and 1782 to the "white standard illuminant" 1736 extend to intersect the outer curved boundary of the CIE color space. The intersection point 1740 closest to a given color point corresponds to the dominant wavelength λ of that color as the wavelength of the pure spectral color (monochromatic) at that intersection point. d The color purity of light of a given chromaticity plotted on a chromaticity diagram is determined by the difference between the dominant wavelength λ and the "white standard illuminant" 1736. d The color purity and dominant wavelength values are tabulated in Table 4.

[0129] Table 5 shows the forward current (I F) for nominal color temperatures (CCT) of 2700K, 3000K, 4000K, 5000K, 5700K, and 6500K. Table 6 lists the measured optical and electrical properties of Device Pack 1 for nominal color temperatures from 2700K to 6500K when operated to produce light with a nominal CRI Ra of 90. As can be seen from Table 5, the CCT of the light produced by Device Pack 1 is increased by a combination of: (i) increasing the blue light component produced by the blue LED, (ii) increasing the green light component produced by the PC green LED, (iii) decreasing the red light component produced by the PC red LED, and (iv) decreasing the white light produced by the white LED. Table 6 illustrates that by selecting the drive currents for the PC red LED, PC green LED, blue LED, and white LED, the color-tunable multi-LED package light-emitting device (Pack 1) can generate white light having a CCT of 2700K to 6500K, an average color rendering index CRI Ra of 90, and a CRI R9 of at least 50, with a luminous efficacy of about 114 to about 124 lm / W. Table 5 also includes the measured CCT of the light generated by Pack 1.

[0130] [Table 5]

[0131] [Table 6]

[0132] 18A-18C are measured luminous characteristics of a color-tunable multi-LED package lighting device (Pack 1) operable to generate light having a CCT ranging from 2700K to 6500K and a CRIRa of 90. FIG. 18A shows the spectra, i.e., normalized luminous intensity (arbitrary units) versus wavelength (nm), for a CCT of 2700K (dotted line), a CCT of 3000K (dashed line), and a CCT of 4000K (solid line). FIG. 18B shows the spectra, i.e., normalized luminous intensity (arbitrary units) versus wavelength (nm). FIG. 18C shows the luminous intensity (arbitrary units) for a CCT of 5000K (dotted line), 5700K (dashed line), and 6500K (solid line), and FIG. 18C shows the chromaticity (color point) of the light produced by the color-tunable multi-LED package lighting device (Pack 1) for nominal CCTs of 2700K, 3000K, 4000K, 5000K, 5700K, and 6500K, with the luminous locus (solid line), blackbody locus (dashed line), and MacAdam ellipse for nominal CCTs from 2700K to 6500K.

[0133] As described herein, the CCT of the light generated by device pack 1 is increased by a combination of: (i) increasing the blue light component generated by the blue LED, (ii) increasing the green light component generated by the PC green LED, (iii) decreasing the red light component generated by the PC red LED, and (iv) decreasing the white light component generated by the white LED. As can be seen from the spectra in Figures 18A and 18B, the CCT of the light generated by device pack 1 is increased by a combination of: (i) increasing the blue light component generated by the blue LED, as shown by arrow 1888, (ii) increasing the green light component generated by the PC green LED, as shown by arrow 1890, and (iii) decreasing the red light component generated by the PC red LED, as shown by arrow 1892.

[0134] Referring to FIG. 18C, one notices that the emission locus (solid line 1894)—the chromaticity of light that device pack 1 can generate—is a curve that closely follows the blackbody locus (dashed line). As explained herein, Δuv (delta uv) is a metric that quantifies the degree to which a given color temperature approximates the blackbody locus. Table 6 lists the Δuv for device pack 1 operating to generate light with a nominal CRI Ra of 90 for nominal CCTs of 2700K, 3000K, 4000K, 5000K, 5700K, and 6500K. As can be seen from this table, Δuv varies from −0.0003 to 0.0031.

[0135] Table 7 shows the drive current (I ) of the PC red LED (R), PC green LED (G), blue LED (B), and white LED (W) in Pack 1 of a color-tunable multi-LED package lighting device that produces light with an average color rendering index of CRI Ra95. F ) are listed for nominal color temperatures (CCT) of 2700K, 3000K, 4000K, 5000K, 5700K, and 6500K. Table 8 lists the optical and electrical characteristics of Device Pack 1 when operated to produce light with a nominal CRI Ra of 95.

[0136] As can be seen from Table 7, the CCT of the light generated by Device Pack 1 is increased by a combination of: (i) increasing the blue light component generated by the blue LED, (ii) increasing the green light component generated by the PC Green LED, (iii) decreasing the red light component generated by the PC Red LED, and (iv) decreasing the white light component generated by the white LED. Table 8 illustrates that by selecting the drive currents of the PC Red LED, PC Green LED, blue LED, and white LED, the color-tunable multi-LED package lighting device (Pack 1) can generate light with a CCT from 2700K to 6500K, an average color rendering index CRI Ra of 95, and a CRI R9 of at least 80, with a luminous efficacy from about 110 to about 115 lm / W.

[0137] [Table 7]

[0138] [Table 8]

[0139] Figure 18D is a CIE 1931 chromaticity diagram illustrating measured chromaticity (color point) values for light emitted by a color-tunable multi-LED package lighting device (Pack 1) operable to emit light having a CRI Ra of 95 for nominal color temperatures of 2700K, 3000K, 4000K, 5000K, 5700K, and 6500K. The diagram also shows the emission locus (solid line), blackbody locus (dashed line), and MacAdam ellipse for CCTs from 2700K to 6500K. Referring to Figure 18D, it is noted that the emission locus (solid line 1931)—the chromaticity locus of light that device Pack 1 can emit—is a curve that closely follows the blackbody locus (dashed line). Table 8 lists the Δuv values for Device Pack 1, operated to produce light with a nominal CRI of 95, for nominal CCTs of 2700K, 3000K, 4000K, 5000K, 5700K, and 6500K. As can be seen from the table, the Δuv values vary from -0.0002 to 0.0023.

[0140] In light of the above, a color-tunable multi-LED lighting device according to an embodiment of the present invention can generate white light with different CCTs and different CRIs Ra (e.g., CRI Ra 90 and CRI Ra 95) by varying the forward drive current of the four LEDs (i.e., red, green, blue, and white). Furthermore, the device according to the present invention has higher luminous efficacy than current color-tunable multi-LED package lighting devices. This combination of features represents a significant breakthrough in the lighting industry, significantly reducing the number of LED package SKUs (Stock Keeping Units) required for different lighting applications.

[0141] The color-tunable multi-LED package lighting device, designated Pack 2, includes the device of FIGS. 13A-13C and a four-cavity package containing a PC red LED in the first cavity, a PC green LED in the second cavity, a blue LED in the third cavity, and a PC white LED in the fourth cavity. The details of the PC red LED, PC green LED, blue LED, and PC white LED are the same as those of Pack 1. In contrast to Pack 1, each InGaN blue-violet-blue LED chip is a multi-junction LED chip with six junctions, i.e., each LED chip contains six LEDs connected in series. The LED chip has a nominal power of 0.5 W and a forward driving voltage of approximately 18 V.

[0142] Table 9 lists the measured optical properties of the PC red LED (R), PC green LED (G), blue LED (B), and white LED (W) in Lighting Device Pack 2. As can be seen from Table 9, the PC red LED has a dominant wavelength (λ d The PC green LED emits red light with a dominant wavelength of 547 nm and a luminous flux of 14.9 lm (luminous efficacy = 33.1 lm / W), the PC green LED emits green light with a dominant wavelength of 547 nm and a luminous flux of 85.8 lm (luminous efficacy = 190.7 lm / W), and the blue LED emits blue light with a dominant wavelength of 456 nm and a luminous flux of 7.6 lm (luminous efficacy = 16.7 lm / W). The white LED emits warm white (WW) light with a nominal CCT of 3000 K (actual CCT 2900 K, Δuv = 0.0015), an average color rendering index (CRI Ra) of approximately 70, and a luminous flux of 66.0 lm (luminous efficacy = 143.8 lm / W).

[0143] [Table 9]

[0144] FIG. 19A is a CIE 1931 chromaticity diagram illustrating the chromaticity (color points) of light emitted by a PC red LED (square), a PC green LED (diamond), a blue LED (triangle), and a white LED (cross), the ANSI CCT center points (solid circles), the device color gamuts (solid lines), and the blackbody locus (dashed lines).

[0145] The CIE chromaticity diagram in Figure 19A shows the chromaticity (color point) 1976 (square) of red light produced by a PC red LED, the chromaticity (color point) 1978 (diamond) of green light produced by a PC green LED, the chromaticity (color point) 1980 (triangle) of blue light produced by a blue LED, and the chromaticity (color point) 1982 (cross) of light produced by a white LED. A line 1984 connecting points 1976, 1978, and 1980 defines a triangle representing the gamut of colors / color temperatures of light that the lighting device pack 2 can produce—i.e., the device can produce light of any color / color temperature on or within this triangle. Note that the lowest CCT of light that the device can produce, which lies on the blackbody locus (dashed line), is approximately 1762 K, corresponding to the intersection of line 1984 connecting points 1976 and 1978 with the blackbody locus.

[0146] Table 10 shows the forward drive current (I) of the PC red LED (R), PC green LED (G), blue LED (B), and white LED (W) in the lighting device pack 2 that produces light with a nominal average color rendering index CRI Ra90. F) for nominal color temperatures of 2700K, 3000K, 3500K, 4000K, 5000K, 5700K, and 6500K. Table 11 lists the measured optical and electrical properties of Device Pack 2 for nominal color temperatures (CCT) from 2700K to 6500K when operated to produce light with a nominal CRI Ra of 90. As can be seen from Table 10, the CCT of the light produced by Device Pack 2 is increased by a combination of: (i) increasing the blue light component produced by the blue LED, (ii) increasing the green light component produced by the PC green LED, (iii) decreasing the red light component produced by the PC red LED, and (iv) decreasing the white light produced by the white LED. Table 11 illustrates that by selecting the drive voltages for the PC red LED, PC green LED, blue LED, and white LED, the color-tunable multi-LED package lighting device (Pack 2) can generate white light having a CCT from 2700K to 6500K with a luminous efficacy from about 124 lm / W to about 145 lm / W, with an average color rendering index CRI Ra of 90 and a CRI R9 of at least 50. Table 11 also includes measurements of the CCT of the light generated by Pack 2.

[0147] [Table 10]

[0148] [Table 11]

[0149] Figure 19B is a CIE 1931 chromaticity diagram illustrating the color points of light generated by a device pack 2 operable to generate light having a CRI Ra of 90 for nominal color temperatures of 2700K, 3000K, 3500K, 4000K, 5000K, 5700K, and 6500K, illustrating emission loci (solid lines) for CCTs from 2700K to 6500K, the blackbody locus (dashed lines), and the MacAdam ellipse. Referring to Figure 19B, the emission locus (solid line 1931)—the chromaticity of light that the device pack 2 can generate—is a curve that closely follows the blackbody locus (dashed line). As described herein, Δuv (delta uv) is a metric that quantifies the degree to which light of a given color temperature approaches the blackbody locus. Table 11 lists Δuv values for Device Pack 2, operated to produce light with a nominal CRI Ra of 90, for nominal CCTs of 2700K, 3000K, 3500K, 4000K, 5000K, 5700K, and 6500K. As can be seen from the table, Δuv varies from 0.0007 to 0.003.

[0150] Multi-LED Package 20A-20C are schematic representations of a multi-LED, multi-cavity package 2012 according to one embodiment of the present invention with a common cathode terminal configuration, where FIG. 20A shows a top view, FIG. 20B shows a cross-sectional side view taken along line AA, FIG. 20C shows a cross-sectional side view taken along line BB, and FIG. 20D shows a top view of a lead frame of the multi-LED package.

[0151] As shown in Figures 20A-20D, the multi-LED package 2012 includes lead frames 2014a-2014d, 2016a-d, and a housing 2018 molded over the lead frames. The housing 2018 includes a first cavity (cup) 2020a for receiving each of the first LED chips 2026a, a second cavity (cup) 2020b for receiving each of the second LED chips 2026b, a third cavity (cup) 2020c for receiving each of the third LED chips 2026c, and a first cavity (cup) 2020d for receiving each of the fourth LED chips 2026d. The LED chips 2026a-2026d are indicated in Figures 20A-20C by dashed rectangles, and bond wires connecting the LED chips to the lead frames are indicated by dashed lines.

[0152] Referring to Figure 20D, various regions of lead frame 2014a-2014d, 2016a-d are indicated by cross-hatching, and the relative positions of housing 2018 and cavities 2020a-2020d are indicated by dashed and dotted lines, respectively. The lead frame includes a central cross-shaped cathode region 2016a-d and four rectangular anode regions 2014a-2014d located at the four open corners of cross-shaped region 2016a-d. As can be seen in Figure 20D, each cavity 2020a-2020d includes on its bottom surface a respective L-shaped region of the cross-shaped cathode regions 2016a-d, which form a common cathode connection to each cavity. As can be seen in Figure 20D, each cavity 2020a-2020d includes a respective rectangular anode region 2014a-2014d on its bottom surface, which provides the anode connection to the cavity. As shown in Figures 20A-20D, each anode region 2014a-2014d of the lead frame extends beyond the outer edges of the housing 2018 to provide a respective anode electrical terminal 2022a-2022d for each cavity 2020a-2020d. Similarly, the cathode regions of the lead frames 2016a-2016d extend beyond opposing edges of the housing to provide common cathode electrical terminals 2024a-d on opposing edges of the housing.

[0153] As described herein, in embodiments, a multi-LED (e.g., four-LED) package can include a single common cathode electrical terminal 2024a-d for each LED chip and a respective anode electrical terminal 2022a-d for each LED chip. In other embodiments of the invention, the multi-LED package can include a respective pair of anode and cathode electrical terminals for each LED. Such a configuration can be beneficial when using multiple multi-LED packages because it allows the LED chips to be connected in series.

[0154] 21A-21D are schematic representations of a multi-LED, four-LED package according to one embodiment of the present invention, the multi-LED package including a pair of anode and cathode electrical terminals for each LED, with FIG. 21A showing a top view, FIG. 21B showing a cross-sectional side view taken along line AA, FIG. 21C showing a cross-sectional side view taken along line BB, and FIG. 21D showing a plan view of a lead frame of the multi-LED package.

[0155] 21A-21D, the multi-LED package 2112 includes lead frames 2114a-2114d, 2116a-2116d, and a housing 2118 molded over the lead frames. The housing 2118 includes a first cavity 2120a for receiving each of the first LED chips 2126a, a second cavity 2120b for receiving each of the second LED chips 2126b, a third cavity 2120c for receiving each of the third LED chips 2126c, and a fourth cavity 2120a for receiving each of the fourth LED chips 2126d. The LED chips 2126a-2126d are indicated by dashed rectangles in FIGS. 21A-21C, and the bond wires connecting the LED chips to the lead frames are indicated by dashed lines.

[0156] Referring to Figure 21D, the various regions 2114a-2114d, 2116a-2116d of the lead frame are indicated by cross-hatching, and the relative positions of the housing 2118 and cavities 2120a-2120d are indicated by dashed and dotted lines, respectively. The lead frame includes four L-shaped cathode regions 2116a-2116d arranged in a cross shape and four rectangular anode regions 2114a-2114d, each anode region located in an open corner of a respective L-shaped region. As can be seen in Figure 21D, each cavity 2120a-2120d includes a respective L-shaped cathode region 2116a-2116d and a respective rectangular anode region 2114a-2114d on its bottom surface. The L-shaped cathode region on the bottom surface of each cavity, in addition to providing the cathode connection, also provides a thermally conductive mounting pad for the LED chip, thereby improving heat dissipation from the LED chip. As can be seen in Figure 21D, each cavity 2120a-2120d includes a respective rectangular anode region 2114a-2114d on its bottom surface, which provides the anode connection to that cavity. As shown in Figures 21A-21D, each anode region 2114a-2114d of the lead frame extends beyond the outer edge of the housing to provide a respective anode electrical terminal 2122a-2122d for each cavity 2120a-2120d. Similarly, each cathode region 2116a-2116d of the lead frame extends beyond the outer edge of the housing 2118 to provide a respective cathode electrical terminal 2124a-2124d on the same edge as the anode electrical terminal of the housing.

[0157] 22A and 22B are schematic representations of a multi-LED (4-LED) package according to another embodiment of the present invention, with FIG. 22A showing a top view and FIG. 22B showing a top view of a leadframe of a multi-LED package 2212. This embodiment is similar to the multi-LED package of FIGS. 21A-21D, except that leadframe regions 2214a-2214d and 2216a-2216d are configured so that each anode terminal 2222a-2222d is aligned with a respective cathode terminal 2224a-2224d and is located on the opposite edge of the housing from the respective cathode terminal 2224a-2224d. This packaging arrangement can be advantageous in linear lighting arrays utilizing multiple multi-LED packages, where it is preferable to connect the LEDs in each cavity in series.

[0158] 22A and 22B, the multi-LED package 2212 includes lead frames 2214a-2214d and 2216a-2216d, and a housing 2218 molded over the lead frames. The housing 2218 includes a first cavity 2220a for receiving each of the first LED chips 2226a, a first cavity 2220b for receiving each of the second LED chips 2226b, a third cavity 2220c for receiving each of the third LED chips 2226c, and a fourth cavity 2220d for receiving each of the fourth LED chips 2226d. The LED chips 2226a-2226d are indicated by dashed rectangles in FIGS. 22A and 22B, and bond wires connecting the LED chips to the lead frames are indicated by dashed lines. 22B, various regions 2214a-2214d, 2216a-2216d of the lead frame are shown, with the respective locations of the housing 2218 and cavities 2220a-2220d indicated by dashed and dotted lines. The lead frame includes four cathode regions 2216a-2216d and four anode regions 2214a-2214d. For the first and second cavities 2220a and 2220b, the cathode regions 2216a and 2216b are zigzag shaped, and the anode regions 2214a and 2214b are elongated. The first and second cavities 2220a and 2220b each include a respective zigzag-shaped cathode region 2216a and 2216b and respective square-shaped ends (indicated by cross-hatching) of elongated anode regions 2214a and 2214b on their bottom surfaces. In this embodiment, the elongated anode region 2214a extends from the first cavity 2220a through the fourth cavity 2220d to the edge of the package opposite the edge of the corresponding cathode region 2216a. Similarly, the elongated anode region 2214b extends from the second cavity 2220b through the third cavity 2220c to the edge opposite the edge of the corresponding cathode region 2216b. In this manner, the (e.g., elongated) anode region extends from one cavity to an adjacent cavity. The anode region may extend between at least two, three, or more cavities.For the third and fourth cavities 2220c and 2220d, the cathode regions 2216c and 2216d are elongated, and the anode regions 2214c and 2214d are zigzag. The third and fourth cavities 2220c and 2220d include square ends (shown cross-hatched) of the elongated cathode regions 2216c and 2216d, respectively, on their bottom surfaces. In this embodiment, the elongated cathode region 2216c extends from the third cavity 2220c through the second cavity 2220b to the edge of the package opposite the edge of the corresponding anode region 2222c. Similarly, in this embodiment, the elongated cathode region 2216d extends from the fourth cavity 2220d through the first cavity 2220a to the edge of the package opposite the edge of the corresponding anode region 2222a. In this manner, a (e.g., elongated) cathode region can extend from one cavity to an adjacent cavity. The zigzag-shaped region on the bottom surface of each cavity provides a thermally conductive mounting pad for the LED chip, thereby improving heat dissipation from the LED chip, in addition to providing electrical connection. As shown in FIGS. 22A and 22B, each anode region of the lead frame extends beyond the outer edge of the housing 2218 to provide a respective anode electrical terminal 2222a-d for each of the cavities 2220a-d. As shown, each of the anode terminals 2222a-d is located along the left edge of the package. Similarly, each cathode region of the lead frame extends beyond the outer edge of the housing to provide a respective cathode electrical terminal 2224a-d on the edge of the housing opposite the edge of the anode electrical terminal. As shown, each of the cathode terminals 2224a-d is disposed along the right edge of the package. At least in this embodiment, for example, the anode and cathode terminals are aligned (or, for example, in the same linear path). [Explanation of symbols]

[0159] List of Reference Numbers Figure 1 1 Multi-LED package 2 Lead Frame 3 Direct-emitting LED chips 3R direct emitting red LED chip 3G direct emitting green LED chip 3B direct emitting blue LED chip 4. Housing 5 Cavities, cups, recesses 6 Translucent encapsulant 7 Anode electrical terminal 7R Anode Electrical Terminal Red LED 7G Anode electrical terminal Green LED 7B Anode electrical terminal Blue LED 8 Cathode electrical terminal 8R cathode electrical terminal red LED 8G Cathode electrical terminal Green LED 8B Cathode electrical terminal Blue LED Figures 2-22 (# = figure number) #10 Red light-emitting device #12 Package #14 Anode lead frame #14a Anode Lead Frame - 1st Cavity #14b Anode Lead Frame - 2nd Cavity #14c Anode Lead Frame - 3rd Cavity #14d Anode Lead Frame - 4th Cavity #14e Common Cathode Lead Frame - Cavities 1-4 #16 Cathode lead frame #16a~d Cathode lead frame - common to cavities 1~4 #16a Cathode Lead Frame - 1st Cavity #16b Cathode Lead Frame - 2nd Cavity #16c Cathode Lead Frame-3rd Cavity #16d Cathode Lead Frame-4th Cavity #18 Housing #18A Bottom of housing #18B Housing side wall #20 Cavity, cup, recess #20a First cavity (first recess) #20b Second cavity (second recess) #20c 1st cavity (3rd recess) #20d 2nd cavity (4th recess) #22 Anode electrical terminal #22a Anode electrical terminal first cavity #22b Anode electrical terminal second cavity #22c Anode electrical terminal 3rd cavity #22d Anode electrical terminal 4th cavity #24 Cathode electrical terminal #24a Cathode electrical terminal first cavity #24b Cathode electrical terminal 2nd cavity #24c Cathode electrical terminal 3rd cavity #24d Cathode electrical terminal 4th cavity #26 Blue-purple to blue LED chip #28 Bond wire #30 Red photoluminescent layer #30A 1st red photoluminescent layer #30B Second red photoluminescent layer #32 Light reflective layer #34 Chromaticity (color point) #36 White Standard Illuminant CIE (1 / 3, 1 / 3) #38 Straight line #40 Main wavelength λ d #42 Complementary color dominant wavelength λ c #44 Blue Peak #46 Blue Peak - Single Layer PC Red LED #48 Blue Peak - Dual PC Red LED #50 Color-tunable multi-LED package light-emitting device #52 Red LED #54 Green LED #56 Blue LED #57 Chromaticity (color point) #57R Chromaticity (color point) - Red LED #57G Chromaticity (Color Point) - Green LED #57B Chromaticity (color point) - Blue LED #57W Chromaticity (color point) - White LED #57CW Chromaticity (color point) - Cool white (CW) LED #57WW Chromaticity (color point) - Warm white (WW) LED #58 Straight line connecting chromaticity (color points) #59 White LED #60 Green photoluminescent layer #62 Green to red photoluminescent layer #64 CW (Cool White) LED #66a 1st LED #66b 2nd LED #66c 3rd LED #66d 4th LED #68 Color-tunable linear lighting device #70 Circuit board #72 Anode Electrical Connector #74 Cathode electrical connector #76 Chromaticity (Color Point) - Red PC LED (Pack 1) #78 Chromaticity (Color Point) - Green PC LED (Pack 1) #80 Chromaticity (Color Point) - Blue LED (Pack 1) #82 Chromaticity (color point) - White LED (Pack 1) #84 Line connecting chromaticity (color points) #86 Lowest CCT chromaticity (color point) #88 Arrow - Blue region of the spectrum #90 Arrow - Green region of the spectrum #92 Arrow - Red region of the spectrum #94 Luminous Trail #96 Highest CCT chromaticity (color point)

Claims

1. a first LED that generates light having a peak emission wavelength between 620 nm and 640 nm; a second LED that generates light having a peak emission wavelength between 500 nm and 565 nm; a third LED that generates light having a dominant wavelength between 430 nm and 480 nm; a fourth LED that generates white light having a CCT in the range of 1800K to 5000K; An illumination device, wherein the first LED comprises a phosphor-converted LED, the phosphor-converted LED comprising a narrowband red phosphor having a FWHM of less than 55 nm, and a broadband red phosphor.

2. The narrow band red phosphor is K 2 SiF 6 :Mn 4+ , K. 2 GeF 6 :Mn 4+ , or K 2 TiF 6 :Mn 4+ 10. The lighting device of claim 1, wherein the narrow band red phosphor is selected from the group consisting of:

3. 3. A lighting device according to claim 1 or 2, wherein the light produced by the lighting device is tunable within a CCT range from 1800K to 6500K.

4. 3. A lighting device according to claim 1 or 2, comprising one layer containing the narrow-band red phosphor and the broad-band red phosphor.

5. 3. A lighting device according to claim 1, comprising a first layer comprising the narrowband red phosphor and a second layer comprising the broadband red phosphor.

6. 3. The lighting device according to claim 1, wherein the first LED emits light having a color purity of at least 90%.

7. 3. The lighting device of claim 1, wherein the second LED comprises a phosphor-converted LED, the phosphor-converted LED comprising a green phosphor.

8. 3. The lighting device according to claim 1, wherein the fourth LED comprises a fourth LED chip that generates light having a dominant wavelength of 400 nm to 480 nm, and a green-red phosphor.

9. 3. A lighting device according to claim 1 or 2, wherein the light produced by the lighting device has a chromaticity within 0.006 Δuv from the blackbody locus for a CCT in the range of 1800K to 6500K and a CRI of 80 to 98.

10. 3. The lighting device of claim 1, wherein at least one of the first LED, the second LED, the third LED, and the fourth LED comprises an LED flip chip or an LED chip comprising multiple LEDs connected in series.

11. a package comprising a lead frame and a housing, the housing comprising a first cup for the first LED, a second cup for the second LED, a third cup for the third LED, and a fourth cup for the fourth LED, the lead frame comprising a common cathode electrode connected to each of the cups and a respective anode electrode connected to each of the cups; or 3. The lighting device of claim 1, further comprising a package comprising a lead frame and a housing, the housing comprising a first cup for the first LED, a second cup for the second LED, a third cup for the third LED, and a fourth cup for the fourth LED, the lead frame comprising a respective cathode electrode connected to each of the cups and a respective anode electrode connected to each of the cups.

12. 12. The lighting device of claim 11, wherein each of the cups comprises an anode terminal connected to the anode electrode and a cathode terminal connected to the cathode electrode, the anode terminal and the cathode terminal for each cup being positioned opposite each other on opposing edges of the housing.

13. The lighting device of claim 1 , wherein at least one of the first LED, the second LED, the third LED, or the fourth LED comprises a chip-scale packaged LED.

14. 1. A lighting device comprising a first LED, a second LED, a third LED, and a fourth LED that emit light of different chromaticities, The light generated by the lighting device is composed of a combination of light generated by the first LED, the second LED, the third LED, and the fourth LED, and the CCT of the light generated by the lighting device is adjustable within a specific range of CCT; the chromaticity of the light generated by the lighting device is within 0.006Δuv of the blackbody locus; An illumination device, wherein the first LED comprises a phosphor-converted red LED, the phosphor-converted red LED comprising a narrowband red phosphor having a FWHM of less than 55 nm, and a broadband red phosphor.

15. The narrow band red phosphor is K 2 SiF 6 :Mn 4+ , K. 2 GeF 6 :Mn 4+ , and K 2 TiF 6 :Mn 4+ and a narrow band red phosphor selected from the group consisting of: 3 :EU 2+ Nitride phosphor, general composition (Sr,Ca)AlSiN 3 :EU 2+ Nitride phosphor, general composition (Sr, Ba) 2 Si 5 N 8 :EU 2+ Nitride phosphor, general 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, and sulfide-based phosphors with a general composition (Sr 1-x M x ) y EU z SiO 5 15. The lighting device of claim 14, wherein 0<x≦0.5, 2.6≦y≦3.3, 0.001≦z≦0.5, and M is a silicate-based phosphor of a divalent metal selected from the group consisting of Ba, Mg, Ca, and Zn.

16. the first LED emits light having a peak emission wavelength of 620 nm to 640 nm; the second LED emits light having a peak emission wavelength of 500 nm to 565 nm; the third LED emits light having a dominant wavelength of 430 nm to 480 nm; 16. A lighting device according to claim 14 or 15, wherein the fourth LED generates white light having a CCT of at least 1800K.

17. 14. A lighting apparatus comprising a circuit board and a plurality of lighting devices according to claim 1 or 13.

18. 18. The lighting device of claim 17, wherein the circuit board is a flexible circuit board.

Images