Apparatus, systems and methods for a multichannel white light illumination source

Abstract

An illumination source includes a housing (101), at least one first light emitting diode (LED) (102) coupled to the housing and configured to emit green-shifted white light, at least one second LED (104) coupled to the housing and configured to emit blue-shifted white light, and at least one third LED (106) coupled to the housing and configured to emit at least one of a red-orange light and an amber light.

Claims

1. An illumination source, comprising: a housing; at least one first light emitting diode (LED) coupled to the housing and configured to emit green-shifted white light; at least one second LED coupled to the housing and including a phosphor configured to emit blue-shifted white light, wherein the blue-shifted white light has CIE 1931 chromaticity coordinates (x, y) within a first region defined by coordinates (0.278, 0.250), (0.292, 0.270), (0.245, 0.285) and (0.267, 0.320); and at least one third LED coupled to the housing and configured to emit at least one of a red-orange light and an amber light.

2. The illumination source of claim 1, wherein the at least one first LED includes a first blue-pump LED having a phosphor configured to emit green-shifted white light.

3. The illumination source of claim 1, wherein the green-shifted white light has CIE 1931 chromaticity coordinates (x, y) within a second region defined by coordinates (0.31, 0.36), (0.34, 0.35), (0.40, 0.54) and (0.42, 0.52).

4. The illumination source of claim 3, wherein the at least one second LED includes a second blue-pump LED.

5. The illumination source of claim 4, wherein each of first blue-pump LED and the second blue-pump LED is free of red phosphor.

6. The illumination source of claim 3, wherein each LED of the at least one second LED is configured to independently emit the blue-shifted white light having CIE 1931 chromaticity coordinates (x, y) within the first region defined by coordinates (0.278, 0.250), (0.292, 0.270), (0.245, 0.285) and (0.267, 0.320), and wherein each LED of the at least one first LED is configured to independently emit the green-shifted white light having CIE 1931 chromaticity coordinates (x, y) within the second region defined by coordinates (0.31, 0.36), (0.34, 0.35), (0.40, 0.54) and (0.42, 0.52).

7. The illumination source of claim 1, wherein the at least one third LED is configured to emit red-orange light having a wavelength of approximately 610 nanometers.

8. The illumination source of claim 1, wherein the at least one third LED is configured to emit amber light having a wavelength of approximately 590 nanometers.

9. The illumination source of claim 1, further comprising a controller coupled to a combination of the at least one first LED, the at least one second LED and the at least one third LED, wherein the controller is configured to variably adjust a light output of the combination so as to generate light corresponding to at least one of a plurality of points near a black body locus in a range of correlated color temperatures (CCT) between approximately 2,400K and 6,500K.

10. The illumination source of claim 9, wherein the combination of the at least one first LED, the at least one second LED and the at least one third LED is configured to generate white light adjustable within each of a plurality of ANSI quadrangles including CCT ranges from approximately 2,400K to 6,500K along the black body locus while maintaining an efficiency of greater than 60 lumens/watt.

11. The illumination source of claim 9, wherein the combination of the at least one first LED, the at least one second LED and the at least one third LED is configured to generate white light adjustable within each of a plurality of ANSI quadrangles including CCT ranges from approximately 2,400K to 6,000K along the black body locus while maintaining a color rendering index (CRI) of greater than 85.

12. The illumination source of claim 1, wherein each LED of the at least one second LED is configured to independently emit the blue-shifted white light having CIE 1931 chromaticity coordinates (x, y) within the first region defined by coordinates (0.278, 0.250), (0.292, 0.270), (0.245, 0.285) and (0.267, 0.320).

13. A method of generating light, the method comprising: generating white light using an illumination source including at least one first light emitting diode (LED) configured to emit green-shifted white light, at least one second LED with a phosphor configured to emit blue-shifted white light, and at least one third LED configured to emit at least one of red-orange light and amber light, wherein the generated white light corresponds to at least one of a plurality of points along a black body locus and wherein the blue-shifted white light has CIE 1931 chromaticity coordinates (x, y) within a first region defined by coordinates (0.278, 0.250), (0.292, 0.270), (0.245, 0.285) and (0.267, 0.320).

14. The method of claim 13, wherein the green-shifted white light has CIE 1931 chromaticity coordinates (x, y) within a second region defined by coordinates (0.31, 0.36), (0.34, 0.35), (0.40, 0.54) and (0.42, 0.52).

15. The method of claim 14, wherein each LED of the at least one second LED is configured to independently emit the blue-shifted white light having CIE 1931 chromaticity coordinates (x, y) within the first region defined by coordinates (0.278, 0.250), (0.292, 0.270), (0.245, 0.285) and (0.267, 0.320), and wherein each LED of the at least one first LED is configured to independently emit the green-shifted white light having CIE 1931 chromaticity coordinates (x, y) within the second region defined by coordinates (0.31, 0.36), (0.34, 0.35), (0.40, 0.54) and (0.42, 0.52).

16. The method of claim 13, further comprising generating variably adjustable white light in a range of correlated color temperatures (CCT) between approximately 2,400K and 6,500K.

17. The method of claim 16, further comprising generating white light adjustable within each of a plurality of ANSI quadrangles including CCT ranges from approximately 2,400K to 6,500K along the black body locus while maintaining an efficiency of greater than 60 lumens/watt.

18. The method of claim 16, further comprising generating white light adjustable within each of a plurality of ANSI quadrangles including CCT ranges from approximately 2,400K to 5,000K with an output of greater than 500 lumens.

19. The method of claim 16, further comprising variably generating the white light corresponding to any of the plurality of points along the black body locus using the combination of the at least one first LED, the at least one second LED and the at least one third LED.

20. The method of claim 13, wherein each LED of the at least one second LED is configured to independently emit the blue-shifted white light having CIE 1931 chromaticity coordinates (x, y) within the first region defined by coordinates (0.278, 0.250), (0.292, 0.270), (0.245, 0.285) and (0.267, 0.320).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings, like reference characters generally refer to the same parts throughout the different views. Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention.

(2) FIG. 1 illustrates a block diagram of a multichannel white light source of illumination in accordance with one embodiment.

(3) FIG. 2 is a CIE 1931 chromaticity diagram illustrating a gamut produced by a multichannel white light source of illumination in accordance with one embodiment.

(4) FIG. 3 is a CIE 1931 chromaticity diagram illustrating a gamut produced by a multichannel white light source of illumination in accordance with another embodiment.

(5) FIG. 4 is a CIE 1931 chromaticity diagram showing several points corresponding to white light as corrected for perception by the human eye at various correlated color temperatures.

(6) FIG. 5 is a CIE 1931 chromaticity diagram illustrating a gamut produced by a multichannel white light source of illumination in accordance with yet another embodiment.

DETAILED DESCRIPTION

(7) As discussed above, one important characteristic of a multichannel LED fixture, in combination with a multichannel lighting control system, is the ability to generate white light at various color points along or near a black body within a large gamut. Applicants have recognized and appreciated that an LED fixture having at least one green-shifted white LED, at least one blue-shifted white LED, and at least one third LED that provides a red component (e.g., red-orange and/or amber) can provide illumination at all or nearly all white color points with hues that correct for the perception of white by the human eye. Such a fixture can further provide high CRI across a broad range of color temperatures with greater overall system efficiency and light output than conventional LED fixtures. In view of the foregoing, various embodiments and implementations of the present invention are directed to apparatus, systems and methods for generating multichannel white light as a source of illumination.

(8) FIG. 1 is a block diagram depicting an LED fixture 100, according to one embodiment. The LED fixture 100 includes a housing 101 and a plurality of LEDs mounted to the housing, including at least one green-shifted white LED 102, at least one blue-shifted white LED 104 and at least one amber and/or red-orange LED 106. The green-shifted white LED 102 may include a blue LED (also referred to as a blue-pump LED) having a phosphor configured to emit green-shifted white light. The blue-shifted white LED 104 may include a blue-pump LED having a phosphor configured to emit blue-shifted white light. The LED fixture 100 may further include a controller 110 for controlling the light output by each LED 102, 104, 106. In some embodiments, the LED fixture 100 is configured to illuminate an environment 150, such as an office (e.g., as represented by a desk 152), auditorium, foyer, theater, retail store, studio, gallery, etc., and particularly environments in which accurate color perception by the human eye 154 is desirable. In various embodiments, the LEDs 102, 104, 106 are arranged within the LED fixture 100 such that the light emitted from each LED 102, 104, 106 mixes in an additive manner to produce light of a particular color (e.g., white light).

(9) In some embodiments, the controller 110 is configured to variably control the illumination generated by the LED fixture 100, for example, by controlling the intensity or brightness of each LED 102, 104, 106 independently of the other LEDs in the fixture. Such variable control may be used to produce illumination of any color within the spectra of each LED 102, 104, 106, either individually or in combination with one another or in combination with additional LEDs having the same or different spectra. In some other embodiments, the illumination generated by the LED fixture 100 may be fixed or non-adjustable. In one embodiment, multiple LED fixtures 100 may be combined or arranged in a manner that allows the controller 110 to provide a common control for the fixture. For example, multiple LED fixtures 100 can be employed to illuminate the environment 150 and the controller 150 can be configured to control the LED fixtures 100 independently or collectively to provide the desired illumination in the environment 150.

(10) FIG. 2 is a CIE 1931 chromaticity diagram illustrating one example of a gamut 230 produced by a multichannel LED fixture, such as the LED fixture 100 of FIG. 1, in accordance with one embodiment. As discussed above, the LED fixture 100 may include at least one green-shifted white LED 102, at least one blue-shifted white LED 104, and at least one third LED 106. In the illustrated embodiment, the blue-shifted white LED 104 is configured to generate light within a first range of CIE coordinates 210, and the green-shifted white LED 102 is configured to generate light within a second range of CIE coordinates 212. In one embodiment, the third LED 106 is configured to generate red-orange light at or about a point 214 on the chromaticity diagram (e.g., at or near a wavelength of 690 nanometers). In some embodiments, the third LED 106 is configured to generate one or more different colors of light, for example, amber (such as described below with respect to FIG. 3). A red-orange and/or amber component can be used in the third LED 106 to expand the gamut, because, in some embodiments, the green-shifted white LED 102 and the blue-shifted white LED 104 do not contain any red phosphor. An LED free of red phosphor can be advantageous because it allows a more efficient generation of the desired LED output, for example, the generation of light corresponding to the chromaticity coordinates that are described below.

(11) The first range of CIE coordinates 210 may have CIE 1931 chromaticity coordinates (x,y) within a range bounded by points 220 on the CIE 1931 chromaticity diagram, and the second range of CIE coordinates 212 may have CIE 1931 chromaticity coordinates (x,y) within a range bounded by points 222. One example of coordinates corresponding to points 220 and 222 is shown in Table 1 below.

(12) TABLE-US-00001 TABLE 1 CIE 1931 Chromaticity Coordinates (x, y). Green-shifted White Blue-shifted White points 222 points 220 Chroma- Chroma- Chroma- Chroma- ticity x ticity y ticity x ticity y Lower Left 0.31 0.36 0.278 0.250 Lower Right 0.34 0.35 0.292 0.270 Upper Left 0.40 0.54 0.245 0.285 Upper Right 0.42 0.52 0.267 0.320

(13) As mentioned above, the gamut 230 corresponds to light generated by the combination of the blue-shifted white LED 104, the green-shifted white LED 102, and the red-orange LED 106. The black body locus is shown by line 240. As can be seen, the gamut 230 includes much of the black body locus 240, meaning that the LED fixture 100 of the present embodiment is capable of producing light across a wide range of color temperatures along and near the black body 240.

(14) Referring now to FIG. 3, a CIE 1931 chromaticity diagram illustrating an example of a gamut 232 produced by a multichannel LED fixture, such as the LED fixture 100 of FIG. 1, is shown in accordance with another embodiment. The present embodiment is substantially similar to the embodiment discussed above with respect to FIG. 2, except that the third LED 106 is configured to generate amber light at or about a point 216 on the chromaticity diagram (e.g., at or near a wavelength of 590 nanometers). The gamut 232 corresponds to the light generated by a combination of the blue-shifted white LED 104, the green-shifted white LED 102, and the amber LED 106. Here too, the gamut 232 includes much of the black body locus 240, which allows the LED fixture 100 of the present embodiment to produce light across a wide range of color temperatures along and near the black body 240. In other embodiments, different light channels and/or additional light channels may be used to expand the gamut.

(15) As discussed above, the human eye does not perceive white light as the white points on the black body locus, but rather perceives white points above and below the black body locus depending on the CCT that is being observed. FIG. 4 illustrates a CIE 1931 chromaticity diagram showing a series of true white light lines 402 connecting white points above and below the black body 240. The chromaticity diagram of FIG. 4 also includes a daylight locus 404 representing the hue of average natural daylight at various correlated color temperatures. Each of the points along the true white lines 402 represent the hue of white light at various color temperatures, corrected for perception by the human eye. At isothermally equivalent points between approximately 2700 K and 4100 K, the true white line 402 is below the black body 240. Between approximately 4100 K and 5000 K, the true white line 402 is above the black body 240 and approximately parallels the daylight locus 404. Above approximately 4100 K, the true white line 402 is above both the black body 240 and the daylight locus 404. It is appreciated that all of the color points along the true white line 402 cannot be achieved using a conventional white LED fixture. In contrast, the LED fixture of at least one embodiment is capable of producing all of the color points along the true white line 402 between approximately 2700 K and 6500 K.

(16) The color of light generated by an LED can be characterized on a CIE 1931 chromaticity diagram with respect to a series of nominal CCT quadrangles (also referred to as ANSI quadrangles) as specified by the ANSI C78.377 standard. ANSI quadrangles are used to specify a range of (x,y) coordinates on the CIE 1931 chromaticity diagram around a standard color temperature. As will be understood by one of skill in the art, ANSI quadrangles may be used as a tolerance specification to characterize the color temperature generated by an LED. FIG. 5 illustrates a CIE 1931 chromaticity diagram showing various ANSI quadrangles 510 for white light overlaid on a gamut 520 representing all colors of light that an LED fixture of at least one embodiment (e.g., LED fixture 100 of FIG. 1) is capable of generating. Line 240 represents the black body locus. As can be seen in FIG. 5, between 2700 K and 5000 K, the gamut 520 includes all white light points along the black body 240, and nearly all white light points within the ANSI quadrangles, indicating that the LED fixture is capable of generating various correlated temperatures of white light along, above and below the black body at least between 2700 K and 5000 K.

(17) As discussed above, some embodiments are capable of producing light having a high output at a high efficiency and with a high CRI. Table 2 below provides a comparison of output, efficiency and CRI between an LED fixture (e.g., LED fixture 100 of FIG. 1) of at least one embodiment and two conventional LED fixtures. In Table 2, RGB refers to performance of a conventional red-green-blue LED fixture, White refers to performance of a conventional adjustable white light LED fixture (such as an INTELLIWHITE series of LED luminaires by Philips Solid-State Lighting Solutions, Inc., of Burlington, Mass.), and LED 100 refers to performance of an LED fixture according to one embodiment (e.g., LED fixture 100).

(18) TABLE-US-00002 TABLE 2 Comparison of Output, Efficiency and CRI. RGB White LED 100 RGB White LED 100 RGB White LED 100 Lumen Lumen Lumen Lm/W Lm/W Lm/W CRI CRI CRI 2400 K 260 520 40 63 24 89 2700 K 282 212 554 41 38 65 27 80 90 4000 K 345 269 728 42 49 71 32 82 91 6500/6000 K 344 312 405 41 56 65 33 75 90

(19) As can be seen in Table 2, embodiments of the LED 100 are capable of producing, at equivalent color temperatures, a higher output (lumens), at a greater efficiency (Lm/W) and with a higher CRI than either the conventional RGB or white fixtures. Notably, the LED 100 is capable of generating light with CRI above 85, which not possible using conventional LED fixtures.

(20) While several inventive embodiments have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and/or structures for performing the function and/or obtaining the results and/or one or more of the advantages described herein, and each of such variations and/or modifications is deemed to be within the scope of the inventive embodiments described herein. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the inventive teachings is/are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific inventive embodiments described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, inventive embodiments may be practiced otherwise than as specifically described and claimed. Inventive embodiments of the present disclosure are directed to each individual feature, system, article, material, kit, and/or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and/or methods, if such features, systems, articles, materials, kits, and/or methods are not mutually inconsistent, is included within the inventive scope of the present disclosure.

(21) All definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and/or ordinary meanings of the defined terms.

(22) It should also be understood that, unless clearly indicated to the contrary, in any methods claimed herein that include more than one step or act, the order of the steps or acts of the method is not necessarily limited to the order in which the steps or acts of the method are recited. Also, reference numerals appearing in the claims in parentheses, if any, are provided merely for convenience and should not be construed as limiting the claims in any way.