Source: https://patents.google.com/patent/EP2460193B1/en
Timestamp: 2020-04-03 06:00:14
Document Index: 621688676

Matched Legal Cases: ['Application No. 11', 'Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 11', 'Application No. 60', 'Art. 54']

EP2460193B1 - Solid state lighting devices including light mixtures - Google Patents
EP2460193B1
EP2460193B1 EP10760820.0A EP10760820A EP2460193B1 EP 2460193 B1 EP2460193 B1 EP 2460193B1 EP 10760820 A EP10760820 A EP 10760820A EP 2460193 B1 EP2460193 B1 EP 2460193B1
EP10760820.0A
EP2460193A1 (en
2009-09-10 Priority to US12/557,036 priority Critical patent/US7821194B2/en
2010-09-03 Application filed by Cree Inc filed Critical Cree Inc
2010-09-03 Priority to PCT/US2010/047822 priority patent/WO2011031635A1/en
2012-06-06 Publication of EP2460193A1 publication Critical patent/EP2460193A1/en
2018-08-01 Publication of EP2460193B1 publication Critical patent/EP2460193B1/en
239000007787 solids Substances 0 title claims description 52
239000000203 mixtures Substances 0 title description 38
OAICVXFJPJFONN-UHFFFAOYSA-N phosphorus Chemical compound data:image/svg+xml;base64,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 data:image/svg+xml;base64,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 [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0 claims description 100
The present application is a continuation in part of U.S. Patent Application No. 11/736,761, filed April 18, 2007 , entitled " LIGHTING DEVICE AND LIGHTING METHOD," which claims the benefit of U.S. Provisional Patent Application No. 60/792,859, filed on Apr. 18, 2006 , entitled "LIGHTING DEVICE AND LIGHTING METHOD" (inventors: Gerald H. Negley and Antony Paul van de Ven), U.S. Provisional Patent Application No. 60/793,524, filed on Apr. 20, 2006 , entitled "LIGHTING DEVICE AND LIGHTING METHOD" (inventors: Gerald H. Negley and Antony Paul van de Ven) and U.S. Provisional Patent Application No. 60/868,134, filed on Dec. 1, 2006 , entitled "LIGHTING DEVICE AND LIGHTING METHOD" (inventors: Gerald H. Negley and Antony Paul van de Ven). The present application is a continuation in part of U.S. Patent Application No. 11/948,021, filed November 30, 2007 , entitled " LIGHTING DEVICE AND LIGHTING METHOD," which claims the benefit of U.S. Provisional Patent Application No. 60/868,134, filed on Dec. 1, 2006 , entitled "LIGHTING DEVICE AND LIGHTING METHOD" (inventors: Gerald H. Negley and Antony Paul van de Ven). The disclosures of each of the above-referenced applications are hereby incorporated by reference in their entireties.
Typically, a solid state light emitting device generates light through the recombination of electronic carriers, i.e. electrons and holes, in a light emitting layer or region. LED devices, or dice, can be mounted in many different ways for many different applications. For example, an LED device can be mounted on a header and enclosed by an encapsulant for protection, wavelength conversion, focusing, dispersion/scattering, etc. LED devices can also be mounted directly to a submount, such as a PCB, and can be coated directly with a phosphor, such as by electrophoresis or other techniques. Accordingly, as used herein, the term "light emitting diode" or "LED" can refer to an organic, inorganic or quantum dot LED device, including an inorganic LED device coated or otherwise provided with phosphor, or to a packaged device, such as a packaged device that includes an LED and that provides electrical contacts, primary optics, heat dissipation, and/or other functional features for the LED.
For larger illumination applications, multiple solid state lighting assemblies, such as lighting panels, may be connected together, for example, in a one or two dimensional array, to form a lighting system. Unfortunately, however, the hue of white light generated by the lighting system may vary from panel to panel, and/or even from lighting device to lighting device. Such variations may result from a number of factors, including variations of intensity of emission from different LEDs, and/or variations in placement of LEDs in a lighting device and/or on a panel. Accordingly, in order to construct a multi-panel lighting system that produces a consistent hue of white light from panel to panel, it may be desirable to measure the hue and saturation, or chromaticity, of light generated by a large number of panels, and to select a subset of panels having a relatively close chromaticity for use in the multi-panel lighting system. This may result in decreased yields and/or increased inventory costs for a manufacturing process. Document WO2009/157999 , which belongs to the state of the art according to Art. 54(3) EPC, describes a solid state apparatus with a first and a second plurality of LEDs having different chromaticities.
A solid state lighting apparatus is provided in line with claim 1. This includes a plurality of light emitting diodes (LEDs). Each of the LEDs includes an LED device configured to emit light having about a first dominant wavelength and a phosphor configured to receive at least some of the light emitted by the LED device and responsively emit light having about a second dominant wavelength. A combined light emitted by the LED device and the phosphor of a first one of the plurality of LEDs has a first color point and a combined light emitted by the LED device and the phosphor of a second one of the plurality of LEDs has a second color point that falls outside a seven step Macadam ellipse centered around the first color point.
The defined area on a 1931 CIE Chromaticity Diagram includes a plurality of bins, each of the plurality of bins having approximately a size of a seven step Macadam ellipse. The first color point falls in a first one of the plurality of bins and the second color point falls within a second one of the plurality of bins.
The apparatus further includes a second plurality of LEDs, each of the second LEDs including an LED device configured to emit light having a third dominant wavelength and a phosphor configured to receive at least some of the light emitted by the LED device and responsively emit light having a fourth dominant wavelength. In some embodiments, the fourth dominant wavelength may be at least about 25 nm higher than the second dominant wavelength. A combined light emitted by the LED device and the phosphor of a first one of the second plurality of LEDs has a third color point and a combined light emitted by the LED device and the phosphor of a second one of the second plurality of LEDs has a fourth color point that falls outside a seven step Macadam ellipse centered around the third color point.
The solid state lighting apparatus further includes a first constant current source, and the first plurality of LEDs may be coupled to the first constant current source and may receive a constant current supplied by the first constant current source. The apparatus may further include a second constant current source, and the second plurality of LEDs may be coupled to the second constant current source and may receive a constant current supplied by the second constant current source.
A solid state lighting apparatus according to the invention includes a current source, and a string of light emitting diodes (LEDs) connected to the current source and configured to emit light in response to a drive current supplied by the current source. Each of the LEDs in the string includes an LED device configured to emit light having a first dominant wavelength and a phosphor configured to receive at least some of the light emitted by the LED device and responsively emit light having about a dominant wavelength that is different from the first dominant wavelength. A combined light emitted by the LED device and the phosphor of a first one of the plurality of LEDs has a first color point and a combined light emitted by the LED device and the phosphor of a second one of the plurality of LEDs has a second color point that falls outside a seven step Macadam ellipse around the first color point.
Figures 4A and 4B illustrate a solid state lighting apparatus according to some embodiments.
Figure 5 is a circuit diagram illustrating interconnection of LEDs in a solid state lighting apparatus according to some embodiments.
Figure 6 is a 1931 CIE Chromaticity Diagram that illustrates combinations of LEDs in a lighting apparatus according to some embodiments.
Figure 7 is a 1931 CIE Chromaticity Diagram that illustrates combinations of LEDs in a lighting apparatus according to further embodiments.
Figure 8 illustrates portions of a solid state lighting apparatus according to further embodiments.
Figure 9 illustrates a portion of a two-dimensional chromaticity space including bin locations and a production locus.
Figure 10 illustrates placement of various type of LEDs on a linear illumination module according to some embodiments.
Figure 11 illustrates a portion of a two-dimensional chromaticity space including the black-body radiation curve and correlated color temperature (CCT) quadrangles of light generally considered white.
Figure 12 illustrates a portion of a 1931 CIE Chromaticity Diagram including a non-white region that has been subdivided into bins.
Figure 13 is a circuit diagram illustrating interconnection of LEDs in a solid state lighting apparatus according to some embodiments.
In a CIE-u'v' chromaticity diagram, such as the 1976 CIE Chromaticity Diagram, chromaticity values are plotted using scaled u- and v-parameters which take into account differences in human visual perception. That is, the human visual system is more responsive to certain wavelengths than others. For example, the human visual system is more responsive green light than red light. The 1976 CIE-u'v' Chromaticity Diagram is scaled such that the mathematical distance from one chromaticity point to another chromaticity point on the diagram is proportional to the difference in color perceived by a human observer between the two chromaticity points. A chromaticity diagram in which the mathematical distance from one chromaticity point to another chromaticity point on the diagram is proportional to the difference in color perceived by a human observer between the two chromaticity points may be referred to as a perceptual chromaticity space. In contrast, in a non-perceptual chromaticity diagram, such as the 1931 CIE Chromaticity Diagram, two colors that are not distinguishably different may be located farther apart on the graph than two colors that are distinguishably different.
As shown in Figure 1, colors on a 1931 CIE Chromaticity Diagram are defined by x and y coordinates (i.e., chromaticity coordinates, or color points) that fall within a generally U-shaped area. Colors on or near the outside of the area are saturated colors composed of light having a single wavelength, or a very small wavelength distribution. Colors on the interior of the area are unsaturated colors that are composed of a mixture of different wavelengths. White light, which can be a mixture of many different wavelengths, is generally found near the middle of the diagram, in the region labeled 100 in Figure 1. There are many different hues of light that may be considered "white," as evidenced by the size of the region 100. For example, some "white" light, such as light generated by sodium vapor lighting devices, may appear yellowish in color, while other "white" light, such as light generated by some fluorescent lighting devices, may appear more bluish in color.
In some embodiments, the device may include LED/phosphor combinations as described in U.S. Patent No. 7,213,940, issued May 8, 2007 , and entitled "LIGHTING DEVICE AND LIGHTING METHOD. As described therein, a lighting device may include solid state light emitters (i.e., LED devices) which emit light having dominant wavelength in ranges of from 430 nm to 480 nm, and a group of phosphors which emit light having dominant wavelength in the range of from 555 nm to 585 nm. A combination of light by the first group of emitters, and light emitted by the group of phosphors produces a sub-mixture of light having x, y color coordinates within a defined area on a 1931 CIE Chromaticity Diagram that is referred to herein as "blue-shifted yellow" or "BSY," illustrated as region 50 in the 1931 CIE Chromaticity Diagram shown in Figure 2. Such non-white light may, when combined with light having a dominant wavelength from 600 nm to 630 nm, produce warm white light.
The solid state lighting device may further include a third LED device that emits light in the blue or green portion of the visible spectrum and that has a dominant wavelength that may be at least about 10 nm greater than a dominant wavelength of the first LED device. That is, a third LED device may be provided that may "fill in" some of the spectral gaps that may be present in light emitted by the lighting device, to thereby improve the CRI of the device. The third LED device may have a dominant wavelength that may be at least about 20 nm greater, and in some embodiments about 50 nm or more greater, than the dominant wavelength of the first LED device.
For example, Figure 3 illustrates a spectrum 200 (intensity vs. wavelength) of light emitted by a blue LED device and a yellow phosphor. The spectrum 200 includes a narrow peak at around 450 nm that represents light emitted by a blue LED and a broad peak centered around 550-560 nm that represents light emitted by a yellow phosphor, such as YAG:Ce, in response to light emitted by the blue LED. A green LED having a dominant wavelength of about 500 nm and an emission spectrum 210 may be provided in addition to the blue LED to provide additional spectral energy in the gap between the blue emission peak and the yellow emission peak.
In some further embodiments, the solid state lighting device may further include yet another LED device that emits light in the red portion of the visible spectrum. The red LED device may further fill in spectral gaps in the spectrum of light emitted by the device, which may further improve CRI. For example, as further shown in Figure 3, a red LED device having a dominant wavelength of about 630 nm and an emission spectrum 220 may provide additional spectral energy in the tail of the yellow emission peak. It will be appreciated that the spectral distributions illustrated in Figure 3 are representative graphs for illustration only, and do not represent actual or simulated data.
Referring to Figures 4A and 4B, a lighting apparatus 110 according to some embodiments is illustrated. The lighting apparatus 110 shown in Figures 4A and 4B is a "can" lighting fixture that may be suitable for use in general illumination applications as a down light or spot light. However, it will be appreciated that a lighting apparatus according to some embodiments may have a different form factor. For example, a lighting apparatus according to some embodiments can have the shape of a conventional light bulb, a pan or tray light, an automotive headlamp, or any other suitable form.
The lighting apparatus 110 generally includes a can shaped outer housing 112 in which a lighting panel 120 is arranged. In the embodiments illustrated in Figures 4A and 4B, the lighting panel 120 has a generally circular shape so as to fit within an interior of the cylindrical housing 112. Light is generated by solid state lighting devices (LEDs) 24A, 24B, which are mounted on the lighting panel 120, and which are arranged to emit light 115 towards a diffusing lens 114 mounted at the end of the housing 112. Diffused light 117 is emitted through the lens 114. In some embodiments, the lens 114 may not diffuse the emitted light 115, but may redirect and/or focus the emitted light 115 in a desired near-field or far-field pattern.
Still referring to Figures 4A and 4B, the solid-state lighting apparatus 110 may include a plurality of first LEDs 24A and a plurality of second LEDs 24B. In some embodiments, the plurality of first LEDs 24A may include white emitting, or non-white emitting, light emitting devices. The plurality of second LEDs 24B may include light emitting devices that emit light having a different dominant wavelength from the first LEDs 24A, so that combined light emitted by the first LEDs 24A and the second LEDs 24B may have a desired color and/or spectral content.
In some embodiments, the LED devices in the LEDs 24A, 24B may have a square or rectangular periphery with an edge length of about 900 µm or greater (i.e. so-called "power chips.") However, in other embodiments, the LED devices 24A, 24B may have an edge length of 500 µm or less (i.e. so-called "small chips"). In particular, small LED devices may operate with better electrical conversion efficiency than power chips. For example, green LED devices with a maximum edge dimension less than 500 microns and as small as 260 microns, commonly have a higher electrical conversion efficiency than 900 micron chips, and are known to typically produce 55 lumens of luminous flux per Watt of dissipated electrical power and as much as 90 lumens of luminous flux per Watt of dissipated electrical power.
Figure 4C is a cross-sectional view of a packaged light emitting diode 24 according to some embodiments. According to some embodiments, a packaged LED 24 includes a submount 42 on which one or more LED devices 43 are mounted. The submount 42 can include electrical traces, wirebond pads, leads, and/or other features that permit the LED devices 43 to be mounted thereon and electrically activated. The submount 42 can also include a heat sink (not shown). An optical encapsulant 44 may surround and protect the LED devices 43 within a cavity defined in, on or by the submount 42. The encapsulant material 44 may enhance coupling of light emission out of the LED devices 43 for better extraction from the package. An optional lens 45 may be mounted on the submount 42 above the LED devices 43 to provide a desired near or far field emission pattern from the package.
The LEDs 24A, 24B in the lighting apparatus 110 may be electrically interconnected in respective strings, as illustrated in the schematic circuit diagram in Figure 5. As shown therein, the LEDs 24A, 24B may be interconnected such that the LEDs 24A are connected in series to form a first string 132A. Likewise, the LEDs 24B may be arranged in series to form a second string 132B. Each string 132A, 132B may be connected to a respective anode terminal 123A, 125A and a cathode terminal 123B, 125B.
Although two strings 132A, 132B are illustrated in Figure 5, it will be appreciated that the lighting apparatus 110 may include more or fewer strings. Furthermore, there may be multiple strings of LEDs 24A, and multiple strings of other colored LEDs 24B.
Figure 6, which is a 1931 CIE Chromaticity Diagram, illustrates the combination of magenta and green LEDs in a lighting device. As illustrated therein, a first LED is provided that emits light at a color point P1 having a dominant wavelength of about 400nm to about 480 nm, in some embodiments from about 430 nm to about 480 nm in some embodiments about 450nm to about 465 nm and in some embodiments about 460 nm. A red phosphor is configured to receive at least some light emitted by the blue LED and to responsively emit light at a color point P2 having a dominant wavelength of about 600 nm to about 630 nm. A combined light emitted by the blue LED and the red phosphor may have a color point P3 that falls into one of the bins B1-B5 illustrated in Figure 6. The bins B1-B5 may be centered around respective color points that are separated from adjacent points by at least a seven step Macadam ellipse, and in some cases by at least a 10 step Macadam ellipse.
Figure 7 is a 1931 CIE Chromaticity Diagram that illustrates the combination of magenta and BSY LEDs in a lighting device. As illustrated therein, a first LED is provided that emits light at a color point P1 having a dominant wavelength of about 400nm to about 480 nm, in some embodiments about 430 nm to about 480 nm, in some embodiments about 450 nm to about 460 nm, and in some embodiments about 450 nm. A red phosphor is configured to receive at least some light emitted by the blue LED and to responsively emit light at a color point P2 having a dominant wavelength of about 600 nm to about 630 nm. A combined light emitted by the blue LED and the red phosphor may comprise BSR light having a color point P3 that falls into one of the bins B1-B5 illustrated in Figure 7. The bins B1-B5 may fall in a region such as the red-purple or purplish red regions 104, 105 illustrated in Figure 1.
In addition to the blue LED/red phosphor combination, a BSY LED having a color point P6 within region 50 is provided. The color point P6 may therefore fall above the planckian locus. The BSR light may be generated by providing a blue LED having a dominant wavelength at a color point P4 of about 430 nm to about 480 nm, in some embodiments about 450 nm to about 465 nm, and in some embodiments about 460 nm in combination with a yellow-emitting phosphor that emits light at a color point P5 to produce the BSY light. Suitable yellow phosphors include Y3Al5O12:Ce3+ (Ce:YAG), CaAlSiN3:Ce3+, and phosphors from the Eu2+-SiAlON-family, and/or the BOSE family. The phosphor may also be doped at any suitable level to provide a desired wavelength of light output. In some embodiments, Ce and/or Eu may be doped into a phosphor at a dopant concentration in a range of about 0.1% to about 20%. Suitable phosphors are available from numerous suppliers, including Mitsubishi Chemical Corporation, Tokyo, Japan, Leuchtstoffwerk Breitungen GmbH, Breitungen, Germany, and Intematix Company, Fremont, California.
Although the color points P1 and P3 are illustrated in Figure 7 as being at different locations, it will be appreciated that the color points P1 and P3 may be at the same location, i.e., the blue LEDs that are used to generate BSR light may have the same dominant wavelength as the blue LEDs that are used to generate BSY light.
A single lighting device may include LEDs from multiple BSR bins and/or multiple BSY bins. For example, referring to Figure 8, a single lighting device may include a plurality of first BSR LEDs 24A-1 and second BSR LEDs 24A-2, and/or a plurality of first BSY LEDs 24B-1 and second BSY LEDs 24B-2. The first BSR LEDs 24A-1 may fall within a first bin of the BSR bins B1 to B5, while the second BSR LEDs 24A-2 may fall within a second bin of the BSR bins B1 to B5 that is different from the first bin. Similarly, the first BSY LEDs 24B-1 may fall within a first portion of the BSY region 50 (Figure 7), while the second BSY LEDs 24B-2 may fall within a second portion of the BSY region 50 that is different from the first portion. The first and second portions of the BSY region 50 may be distinguished in that they may be centered around color points that are at separated by at least a seven step Macadam ellipse, and in some cases by at least a ten step Macadam ellipse. The bins B1-B5 may be selected or defined such that a line segment between any point in the bins B1-B5 and any point in the BSY region 50 may cross the planckian locus at a point that is between about 2500 K and 6000K.
As an example, consider the binning system for white LEDs illustrated in Figure 9, which is a portion of a 1931 CIE chromaticity diagram. As shown therein, a particular production system produces LEDs having a chromaticity falling within a production locus P. The locus P represents the variation boundaries in two-dimensional chromaticity space for the distribution of a production recipe, for example. The two-dimensional chromaticity space may, for example, be the 1931 CIE chromaticity space. The numbered polygons 1-12 illustrated in Figure 9 are chromaticity bins. As each member of the LED production population is tested, the chromaticity of the LED is determined, and the LED is placed in an appropriate bin. Those members of the population having the same bin associations may be sorted and grouped together. It is common for a luminaire manufacturer to use members from one of these bins to make assemblies to assure uniformity within a multi-LED assembly and similarity between all such assemblies. However, much of the locus P would be left unused in such a situation.
Referring still to Figure 9, a production population chromaticity locus P is shown as at least partially covering five bin groups 1-5.
Referring to Figure 10, a linear illumination module 20 is shown including a plurality of LED devices 24 for use in illumination assembly. As shown in Figure 10, two alternating groups of LED devices are labeled a group A and group B. The LED devices 24 are grouped into groupings 60, referred to herein as metameric groupings 60A-60D. Chromaticities of the LEDs 24 of the metameric groupings 60A-60D are selected so that a combined light generated by a mixture of light from each of the LEDs 24 of the metameric groupings 60A-60D may include light having about a target chromaticity T. Two points in a two-dimensional chromaticity space are considered to have about the same chromaticity if one point is within a seven step Macadam ellipse of the other point, or vice versa. A Macadam ellipse is a closed region around a center point in a two-dimensional chromaticity space, such as the 1931 CIE chromaticity space, that encompasses all points that are visually indistinguishable from the center point. A seven-step Macadam ellipse captures points that are indistinguishable to an ordinary observer within seven standard deviations.
In some embodiments, the chromaticity of each of the LEDs 24 of a metameric groupings 60A-60D may be within about a seven step Macadam ellipse about a point on a black-body radiation curve on a 1931 CIE chromaticity space from a correlated color temperature (CCT) of 4000K to 8000K. Thus, each of the LEDs 24 may individually have a chromaticity that is within a region that is generally considered to be white. For example, Figure 11 illustrates a portion of a 1931 CIE diagram including the black-body radiation curve 70 and a plurality of CCT quadrangles, or bins, 72. Furthermore, Figure 11 illustrates a plurality of 7-step Macadam ellipses 74 around various points 76 on or near the black-body radiation curve 70.
Although binary groupings are illustrated in Figure 9, it will be appreciated that ternary, quaternary and higher-order versions may also be utilized, in which a metameric grouping includes three or more LED devices.
For example, referring to Figure 12, a portion of a 1931 CIE Chromaticity Diagram including a BSY region 50 is illustrated therein. The BSY region 50 is further subdivided into a plurality of sub-regions, or bins, 220A to 220K, each of which is defined to have a size that is approximately the size of a seven step Macadam ellipse centered about a point near the middle of the bin, as illustrated in Figure 12.
Accordingly, referring to Figure 13, some embodiments provide a solid state lighting apparatus that includes a plurality of light emitting diodes (LEDs) 24A-1 to 24A-4 connected in series to form an LED string 132A. Each of the LEDs includes an LED device configured to emit light having a dominant wavelength of, for example, about 430 nm to 480 nm and a phosphor configured to receive at least some of the light emitted by the LED device and responsively emit light having about a second dominant wavelength, of, for example, about 550 nm to about 580 nm. LEDs in the string 132A may have color points that fall into different bins 220A-220K. That is, a combined light emitted by the LED device and the phosphor of a first one of the plurality of LEDs has a first color point that falls within a first one of the bins 220A-22K, and a combined light emitted by the LED device and the phosphor of a second one of the plurality of LEDs has a second color point that falls within a different one of the bins 220A-22K. In particular, the second color point may fall outside a seven step Macadam ellipse around the first color point.
As illustrated in Figure 12, however, the first color point and the second color point may each fall within the BSY area 50 on a 1931 CIE Chromaticity Diagram. As noted above, the BSY area 50 is a polygon defined by points having x, y coordinates of (0.32, 0.40), (0.36, 0.48), (0.43, 0.45), (0.42, 0.42), (0.36, 0.38). Accordingly, the light generated by the string 132A may have a non-white color point that falls outside a ten-step Macadam ellipse around any point on the planckian locus between 2000 Kelvin and 8000 Kelvin.
The apparatus further includes a second plurality of LEDs 24B-1 to 24B-4 connected in series to form a string 132B. Each of the second LEDs 24B-1 to 24B-4 includes an LED device configured to emit light having a third dominant wavelength and a phosphor configured to receive at least some of the light emitted by the LED device and responsively emit light having a fourth dominant wavelength. According to the invention, the fourth dominant wavelength may be at least about 25 nm higher than the second dominant wavelength. That is, the phosphors may emit substantially different wavelengths of light. A combined light emitted by the LED device and the phosphor of a first one of the second plurality of LEDs has a third color point and a combined light emitted by the LED device and the phosphor of a second one of the second plurality of LEDs has a fourth color point that falls outside a seven step Macadam ellipse of the third color point. That is, the second LED string 132B includes LEDs having different color points.
a first plurality of light emitting diodes, LEDs (24A-1, 24A-4) connected in a first series, each of the LEDs comprising an LED device configured to emit light having about a first dominant wavelength and a phosphor configured to receive at least some of the light emitted by the LED device and responsively emit light having about a second dominant wavelength, wherein each of the plurality of LED devices emits substantially the same colour of light and each of the first plurality of LEDs comprises the same phosphor;
a first constant current source (230A), wherein the first plurality of LEDs (24A-1, 24A-4) is coupled to the first constant current source, and wherein each LED of the first plurality of LEDs is energized by a reference current supplied by the first constant current source;
a second plurality of LEDs (24B-1, 24B-4) connected in a second series, each of the second plurality of LEDs comprising an LED device configured to emit light having a third dominant wavelength and a phosphor configured to receive at least some of the light emitted by the LED device and responsively emit light having a fourth dominant wavelength, wherein the fourth dominant wavelength is at least about 25 nm higher than the second dominant wavelength;
wherein a combined light emitted by the LED device and the phosphor of a first one of the first plurality of LEDs (24A-1, 24A-4) has a first color point and a combined light emitted by the LED device and the phosphor of a second one of the first plurality of LEDs (24A-1, 24A-4) has a second color point that falls outside a seven step Macadam ellipse around the first color point, wherein a combined light emitted by the LED device and the phosphor of a first one of the second plurality of LEDs (24B-1, 24B-4) has a third color point and a combined light emitted by the LED device and the phosphor of a second one of the second plurality of LEDs (24B-1, 24B-4) has a fourth color point that falls outside a seven step Macadam ellipse around the third color point, wherein the first color point and the second color point each fall within a region (50) defined on a 1931 CIE Chromaticity Diagram that is subdivided into bins (220A, 220B), each of which is defined to have a size that is approximately the size of a seven step Macadam ellipse centred about a point near the middle of the bin, and wherein the first color point falls in a first one of the plurality of bins and the second color point falls within a second, different one of the plurality of bins.
The solid state lighting apparatus of Claim 1, wherein the first color point and the second color point each fall within a region (50) defined on a 1931 CIE Chromaticity Diagram wherein the defined region is enclosed by first, second, third, fourth and fifth line segments, said first line segment connecting a first point to a second point, said second line segment connecting said second point to a third point, said third line segment connecting said third point to a fourth point, said fourth line segment connecting said fourth point to a fifth point, and said fifth line segment connecting said fifth point to said first point, said first point having x, y coordinates of 0.32, 0.40, said second point having x, y coordinates of 0.36, 0.48, said third point having x, y coordinates of 0.43, 0.45, said fourth point having x, y coordinates of 0.42, 0.42, and said fifth point having x, y coordinates of 0.36, 0.38.
The solid state lighting apparatus of Claim 2, wherein a chromaticity of combined light emitted by the first plurality of LEDs has a color point that falls within the defined region on a 1931 CIE Chromaticity Diagram.
The solid state lighting apparatus of Claim 2, wherein a chromaticity of combined light emitted by the first plurality of LEDs has a color point that falls outside a ten-step Macadam ellipse around any point on the planckian locus between 2000 Kelvin and 8000 Kelvin.
The solid state lighting apparatus of Claim 1, wherein the first dominant wavelength is from about 430 nm to about 480 nm.
The solid state lighting apparatus of Claim 1, wherein the first dominant wavelength is from about 500 nm to about 530 nm.
The solid state lighting apparatus of Claim 5 or Claim 6, wherein the second dominant wavelength is from about 600 nm to about 630 nm.
The solid state lighting apparatus of Claim 5 or Claim 6, wherein the second dominant wavelength is from about 550 nm to about 580 nm.
The solid state lighting apparatus of Claim 1, wherein the first dominant wavelength is from about 430 nm to about 480 nm, the second dominant wavelength is from about 550 nm to about 580 nm, the third dominant wavelength is from about 430 nm to about 480 nm, and the fourth dominant wavelength is from about 600 nm to about 630 nm.
The solid state lighting apparatus of Claim 1, wherein the first dominant wavelength is from about 430 nm to about 480 nm, the second dominant wavelength is from about 550 nm to about 580 nm, the third dominant wavelength is from about 500 nm to about 530 nm, and the fourth dominant wavelength is from about 600 nm to about 630 nm.
The solid state lighting apparatus of Claim 1, further comprising a second constant current source (230B), wherein the second plurality of LEDs is coupled to the second constant current source and receives a constant current supplied by the second constant current source.
The solid state lighting apparatus of Claim 1, wherein the third dominant wavelength is from about 600 nm to about 630 nm.
The solid state lighting apparatus of Claim 1, wherein a line segment on a 1931 CIE Chromaticity diagram between a color point of combined light emitted by the first plurality of LEDs and the color point of light emitted by the second plurality of LEDs crosses the planckian locus between about 2500 Kelvin and 4500 Kelvin.
EP10760820.0A 2006-04-18 2010-09-03 Solid state lighting devices including light mixtures Active EP2460193B1 (en)
US12/557,036 US7821194B2 (en) 2006-04-18 2009-09-10 Solid state lighting devices including light mixtures
EP2460193A1 EP2460193A1 (en) 2012-06-06
EP2460193B1 true EP2460193B1 (en) 2018-08-01
EP10760820.0A Active EP2460193B1 (en) 2006-04-18 2010-09-03 Solid state lighting devices including light mixtures
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2009-09-10 US US12/557,036 patent/US7821194B2/en active Active
2010-09-03 KR KR1020127008215A patent/KR20120093181A/en not_active Application Discontinuation
2010-09-03 CN CN201080052740.XA patent/CN102714260B/en active IP Right Grant
2010-09-03 JP JP2012528845A patent/JP2013504876A/en active Pending
2010-09-03 WO PCT/US2010/047822 patent/WO2011031635A1/en active Application Filing
2010-09-03 EP EP10760820.0A patent/EP2460193B1/en active Active
2010-09-09 TW TW099130528A patent/TW201115059A/en unknown
2010-10-25 US US12/911,434 patent/US8212466B2/en active Active
CN102714260B (en) 2017-09-05
US7821194B2 (en) 2010-10-26
US8212466B2 (en) 2012-07-03
US20100002440A1 (en) 2010-01-07
WO2011031635A1 (en) 2011-03-17
CN102714260A (en) 2012-10-03
TW201115059A (en) 2011-05-01
US20110037413A1 (en) 2011-02-17
KR20120093181A (en) 2012-08-22
EP2460193A1 (en) 2012-06-06
JP2013504876A (en) 2013-02-07
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US8950892B2 (en) 2015-02-10 Methods for combining light emitting devices in a white light emitting apparatus that mimics incandescent dimming characteristics and solid state lighting apparatus for general illumination that mimic incandescent dimming characteristics
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