Systems and methods for providing tunable warm white light

• US 10,555,397 B2
• Filed: 07/30/2018
• Issued: 02/04/2020
• Est. Priority Date: 01/28/2016
• Status: Active Grant

• Current Assignee: Korrus Incorporated (MKD Electric, Inc.)
• Original Assignee: EcoSense Lighting Inc.
• Inventors: Petluri, Raghuram L. V, Pickard, Paul Kenneth
• Primary Examiner(s): Chan, Wei (Victor) Y
• Application Number:
  US16/049,786
• Publication Number:
  US 20190098720A1
• Time in Patent Office: 554 Days
• Field of Search: 315297, 315151, 315156, 315177, 315185 R
• CPC Class Codes: F21K 9/64 using wavelength conversion means distinct or spaced from the light-generating element, e.g. a remote phosphor layer
• CPC Class Codes: F21V 23/0442 activated by means of a sensor, e.g. motion or photodetectors
• CPC Class Codes: F21Y 2103/10 comprising a linear array of point-like light-generating elements
• CPC Class Codes: F21Y 2113/13 comprising an assembly of point-like light sources
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H01L 25/13 the devices being of a type provided for in group H01L33/00
• CPC Class Codes: H01L 2933/0041 relating to wavelength conversion elements
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: H05B 45/20 Controlling the colour of the light
• CPC Class Codes: H05B 45/24 using electrical feedback from LEDs or from LED modules

Abstract

The present disclosure provides methods for generating tunable white light. The methods include using a plurality of LED strings to generate light with color points that fall within white, red, and cyan color ranges, with each LED string being driven with a separately controllable drive current in order to tune the generated light output.

Claims

1. A method of generating white light, the method comprising:

producing light from a first light emitting diode (“

LED”

) string that comprises a blue LED with a peak wavelength of between about 405 nm and about 470 nm;

producing light from a second light emitting diode (“

LED”

) string that comprises a blue LED with a peak wavelength of between about 405 nm and about 470 nm;

producing light from a third light emitting diode (“

LED”

) string that comprises a blue LED with a peak wavelength of between about 405 nm and about 470 nm;

passing the light produced by each of the first, second, and third LED strings through one of a plurality of respective luminophoric mediums to produce a first unsaturated light, a second unsaturated light, and a third unsaturated light, respectively;

combining the first unsaturated light, the second unsaturated light, and the third unsaturated light together into a fourth unsaturated light;

wherein the first unsaturated light has a first color point within a 7-step MacAdam ellipse around any point on the black body locus having a correlated color temperature between about 3500K and about 6500K;

wherein the second unsaturated light has a second color point within a red color range defined by the spectral locus between the constant CCT line of 1600K and the line of purples, the line of purples, a line connecting the ccx, ccy color coordinates (0.61, 0.21) and (0.47, 0.28), and the constant CCT line of 1600K;

wherein the second unsaturated light has a spectral power distribution that falls between 0.0% to 14.8% for wavelengths between 380 nm to 420 nm, between 2.1% to 15% for wavelengths between 421 nm to 460 nm, between 2.0% to 6.7% for wavelengths between 461 nm to 500 nm, between 1.4% to 12.2% for wavelengths between 501 nm to 540 nm, between 8.7% to 24.7% for wavelengths between 541 nm to 580 nm, between 48.5% and 102.8% for wavelengths between 581 nm to 620 nm, 100% for wavelengths between 621 nm to 660 nm, between 1.8% to 74.3% for wavelengths between 661 nm to 700 nm, between 0.5% to 29.5% for wavelengths between 701 nm to 740 nm, and between 0.3% to 9.0% for wavelengths between 741 nm to 780 nm;

wherein the third unsaturated light has a third color point within a cyan color range defined by a line connecting the ccx, ccy color coordinates (0.18, 0.55) and (0.27, 0.72), the constant CCT line of 9000K, the Planckian locus between 9000K and 1800K, the constant CCT line of 1800K, and the spectral locus; and

wherein fourth unsaturated light corresponds to at least one of a plurality of points along a predefined path near the black body locus in the 1931 CIE Chromaticity Diagram within a 7-step MacAdam ellipse around any point on the black body locus having a correlated color temperature between about 1800K and about 3200K.

2. The method of claim 1, wherein the first unsaturated light has a first color point within a white color range defined by a polygonal region on the 1931 CIE Chromaticity Diagram defined by the following ccx, ccy color coordinates:

(0.4006, 0.4044), (0.3736, 0.3874), (0.3670, 0.3578), (0.3898, 0.3716).

3. The method of claim 1, wherein the white color range comprises a single 5-step MacAdam ellipse with center point (0.3818, 0.3797) with a major axis “

a”

of 0.01565, minor axis “

b”

of 0.00670, with an ellipse rotation angle θ

of 52.70°

relative to a line of constant ccy values.

4. The method of claim 1, wherein the red color range comprises a region on the 1931 CIE Chromaticity Diagram defined by a 20-step MacAdam ellipse at 1200K, 20 points below the Planckian locus.

5. The method of claim 1, wherein the cyan color range comprises a region on the 1931 CIE Chromaticity Diagram defined by region bounded by (0.360, 0.495), (0.371, 0.518), (0.388, 0.522), and (0.377, 0.499).

6. The method of claim 1, wherein the white color range comprises a single 3-step MacAdam ellipse with center point (0.3818, 0.3797) with a major axis “

a”

of 0.00939, minor axis “

b”

of 0.00402, with an ellipse rotation angle θ

of 53.7°

relative to a line of constant ccy values.

7. The method of claim 1, wherein the method comprises generating fourth unsaturated light corresponding to a plurality of points along the predefined path with the light generated at each point having light with one or more of Rf greater than or equal to about 88, Rg greater than or equal to about 95 and less than or equal to about 105.

8. The method of claim 1, wherein the method comprises generating fourth unsaturated light corresponding to a plurality of points along the predefined path with the light generated at each point having light with one or more of Rf greater than or equal to about 85, Rg greater than or equal to about 90 and less than or equal to about 110.

9. The method of claim 1, wherein the method comprises generating fourth unsaturated light corresponding to a plurality of points along the predefined path with the light generated at each point having light with one or more of Rf greater than or equal to about 88, Rg greater than or equal to about 96 and less than or equal to about 104.

10. The method of claim 1, wherein the method comprises generating fourth unsaturated light corresponding to a plurality of points along the predefined path with the light generated at each point having light with one or more of:

Rf greater than or equal to about 88; and

Rg greater than or equal to about 96 and less than or equal to about 104.

11. The method of claim 1, wherein the third unsaturated light has a spectral power distribution that falls between 3.9% to 130.6% for wavelengths between 380 nm to 420 nm, 100% for wavelengths between 421 nm to 460 nm, between 112.7% to 553.9% for wavelengths between 461 nm to 500 nm, between 306.2% to 5472.8% for wavelengths between 501 nm to 540 nm, between 395.1% to 9637.9% for wavelengths between 541 nm to 580 nm, between 318.2% to 12476.9% for wavelengths between 581 nm to 620 nm, between 245% to 13285.5% for wavelengths between 621 nm to 660 nm, between 138.8% to 6324.7% for wavelengths between 661 nm to 700 nm, between 39.5% to 1620.3% for wavelengths between 701 nm to 740 nm, and between 10.3% to 344.7% for wavelengths between 741 nm to 780 nm.

12. The method of claim 1, wherein the second unsaturated light has a spectral power distribution that falls between 0% to 0.1% for wavelengths between 380 nm to 420 nm, between 2.3% to 2.7% for wavelengths between 421 nm to 460 nm, between 4.3% to 5% for wavelengths between 461 nm to 500 nm, between 9.5% to 10.2% for wavelengths between 501 nm to 540 nm, between 24.6% to 24.7% for wavelengths between 541 nm to 580 nm, between 60.4% to 61% for wavelengths between 581 nm to 620 nm, 100% for wavelengths between 621 nm to 660 nm, between 51.5% to 71.7% for wavelengths between 661 nm to 700 nm, between 12.4% to 27.8% for wavelengths between 701 nm to 740 nm, and between 2.4% to 8.4% for wavelengths between 741 nm to 780 nm.

13. The method of claim 1, wherein the third unsaturated light has a spectral power distribution that falls between 3.9% to 30.6% for wavelengths between 380 nm to 420 nm, 100% for wavelengths between 421 nm to 460 nm, between 112.7% to 553.9% for wavelengths between 461 nm to 500 nm, between 306.2% to 2660.6% for wavelengths between 501 nm to 540 nm, between 395.1% to 4361.9% for wavelengths between 541 nm to 580 nm, between 318.2% to 3708.8% for wavelengths between 581 nm to 620 nm, between 245% to 2223.8% for wavelengths between 621 nm to 660 nm, between 138.8% to 712.2% for wavelengths between 661 nm to 700 nm, between 39.5% to 285.6% for wavelengths between 701 nm to 740 nm, and between 10.3% to 99.6% for wavelengths between 741 nm to 780 nm.

14. The method of claim 1, wherein the method further comprises receiving input from one or more of an end user of the semiconductor light emitting device and one or more sensors measuring a characteristic associated with the performance of the first LED string, the second LED string, or the third LED string.

15. The method of claim 1, wherein the method comprises generating fourth unsaturated light corresponding to a plurality of points along the predefined path, wherein:

the light generated at points along about 85% of the predefined path has Rf greater than or equal to about 90;

the light generated at points along about 85% of the predefined path has Rg greater than or equal to about 95 and less than or equal to about 105;

or both.

16. The method of claim 1, wherein the method comprises generating fourth unsaturated light corresponding to a plurality of points along the predefined path with the light generated at each point having light with one or more of Ra greater than or equal to about 90, R9 greater than or equal to about 60.

17. The method of claim 1, wherein the method comprises generating fourth unsaturated light corresponding to a plurality of points along the predefined path with the light generated at each point having light with one or more of:

Ra greater than or equal to about 90; and

R9 greater than or equal to about 60.

18. The method of claim 1, wherein the method comprises generating fourth unsaturated light corresponding to a plurality of points along the predefined path, wherein:

the light generated at points along about 85% of the predefined path has Ra greater than or equal to about 90;

the light generated at points along about 85% of the predefined path has R9 greater than or equal to about 65;

or both.

19. The method of claim 1, wherein the red color range comprises a region on the 1931 CIE Chromaticity Diagram defined by region bounded by lines connecting (0.576, 0.393), (0.583, 0.400), (0.604, 0.387), and (0.597, 0.380).

40. The method of claim 1, wherein the third LED string comprises a blue LED with a peak wavelength of between about 440 nm and about 465 nm.

20. A semiconductor light emitting device, comprising:

a first light emitting diode (“

LED”

) string that comprises a first LED that has a first recipient luminophoric medium that comprises a first luminescent material, wherein the first LED and first luminophoric medium together emit a first unsaturated light having a first color point within a white color range defined by a polygonal region on the 1931 CIE Chromaticity Diagram defined by the following ccx, ccy color coordinates;

(0.4006, 0.4044), (0.3736, 0.3874), (0.3670, 0.3578), (0.3898, 0.3716);

a second LED string that comprises a second LED that has a second recipient luminophoric medium that comprises a second luminescent material, wherein the second LED and second luminophoric medium together emit a second unsaturated light having a second color point within a red color range defined by the spectral locus between the constant CCT line of 1600K and the line of purples, the line of purples, a line connecting the ccx, ccy color coordinates (0.61, 0.21) and (0.47, 0.28), and the constant CCT line of 1600K;

a third LED string that comprises a third LED that has a third recipient luminophoric medium that comprises a third luminescent material, wherein the third LED and third luminophoric medium together emit a third unsaturated light having a third color point within a cyan color range defined by a line connecting the ccx, ccy color coordinates (0.18, 0.55) and (0.27, 0.72), the constant CCT line of 9000K, the Planckian locus between 9000K and 1800K, the constant CCT line of 1800K, and the spectral locus; and

a drive circuit;

wherein the drive circuit is configured to adjust the relative values of first, second, third, and fourth drive currents provided to the LEDs in the first, second, and third LED strings, respectively, to adjust a fourth color point of a fourth unsaturated light that results from a combination of the first, second, and third unsaturated light; and

wherein the second unsaturated light has a spectral power distribution that falls between 0.0% to 14.8% for wavelengths between 380 nm to 420 nm, between 2.1% to 15% for wavelengths between 421 nm to 460 nm, between 2.0% to 6.7% for wavelengths between 461 nm to 500 nm, between 1.4% to 12.2% for wavelengths between 501 nm to 540 nm, between 8.7% to 24.7% for wavelengths between 541 nm to 580 nm, between 48.5% and 102.8% for wavelengths between 581 nm to 620 nm, 100% for wavelengths between 621 nm to 660 nm, between 1.8% to 74.3% for wavelengths between 661 nm to 700 nm, between 0.5% to 29.5% for wavelengths between 701 nm to 740 nm, and between 0.3% to 9.0% for wavelengths between 741 nm to 780 nm.

21. The semiconductor light emitting device of claim 20,

wherein the LEDs in the first, second, and third LED strings comprise blue LEDs having a peak wavelength between about 405 nm and about 485 nm.

22. The semiconductor light emitting device of claim 20,

wherein the white color range comprises a region defined by a polygonal region on the 1931 CIE Chromaticity Diagram defined by the following ccx, ccy color coordinates:

(0.4006, 0.4044), (0.3736, 0.3874), (0.3670, 0.3578), (0.3898, 0.3716).

23. The semiconductor light emitting device of claim 20,

wherein the white color range comprises a single 5-step MacAdam ellipse with center point (0.3818, 0.3797) with a major axis “

a”

of 0.01565, minor axis “

b”

of 0.00670, with an ellipse rotation angle θ

of 52.70°

relative to a line of constant ccy values.

24. The semiconductor light emitting device of claim 20,

wherein the red color range comprises a region on the 1931 CIE Chromaticity Diagram defined by a 20-step MacAdam ellipse at 1200K, 20 points below the Planckian locus.

25. The semiconductor light emitting device of claim 20,

wherein the cyan color range comprises a region on the 1931 CIE Chromaticity Diagram defined by region bounded by (0.360, 0.495), (0.371, 0.518), (0.388, 0.522), and (0.377, 0.499).

26. The semiconductor light emitting device of claim 20,

wherein the white color range comprises a single 3-step MacAdam ellipse with center point (0.3818, 0.3797) with a major axis “

a”

of 0.00939, minor axis “

b”

of 0.00402, with an ellipse rotation angle θ

of 53.7°

relative to a line of constant ccy values.

27. The semiconductor light emitting device of claim 20,

wherein the drive circuit is configured to adjust the fourth color point so that it falls within a 7-step MacAdam ellipse around any point on the black body locus having a correlated color temperature between about 1800K and about 3200K.

28. The semiconductor light emitting device of claim 27,

wherein the light emitting device is configured to generate the fourth unsaturated light corresponding to a plurality of points along a predefined path with the light generated at each point having light with one or more of Ra greater than or equal to about 90, R9 greater than or equal to about 60.

29. The semiconductor light emitting device of claim 20,

wherein the drive circuit is configured to adjust the fourth color point so that it falls within a 7-step MacAdam ellipse around any point on the black body locus having a correlated color temperature between about 1800K and about 3200K;

and

wherein the light emitting device is configured to generate the fourth unsaturated light corresponding to a plurality of points along a predefined path with the light generated at each point having light with one or more of;

Ra greater than or equal to about 90; and

R9 greater than or equal to about 60.

30. The semiconductor light emitting device of claim 20, wherein the third unsaturated light has a spectral power distribution that falls between 3.9% to 130.6% for wavelengths between 380 nm to 420 nm, 100% for wavelengths between 421 nm to 460 nm, between 112.7% to 553.9% for wavelengths between 461 nm to 500 nm, between 306.2% to 5472.8% for wavelengths between 501 nm to 540 nm, between 395.1% to 9637.9% for wavelengths between 541 nm to 580 nm, between 318.2% to 12476.9% for wavelengths between 581 nm to 620 nm, between 245% to 13285.5% for wavelengths between 621 nm to 660 nm, between 138.8% to 6324.7% for wavelengths between 661 nm to 700 nm, between 39.5% to 1620.3% for wavelengths between 701 nm to 740 nm, and between 10.3% to 344.7% for wavelengths between 741 nm to 780 nm.

31. The semiconductor light emitting device of claim 20, wherein the second unsaturated light has a spectral power distribution that falls between 0% to 0.1% for wavelengths between 380 nm to 420 nm, between 2.3% to 2.7% for wavelengths between 421 nm to 460 nm, between 4.3% to 5% for wavelengths between 461 nm to 500 nm, between 9.5% to 10.2% for wavelengths between 501 nm to 540 nm, between 24.6% to 24.7% for wavelengths between 541 nm to 580 nm, between 60.4% to 61% for wavelengths between 581 nm to 620 nm, 100% for wavelengths between 621 nm to 660 nm, between 51.5% to 71.7% for wavelengths between 661 nm to 700 nm, between 12.4% to 27.8% for wavelengths between 701 nm to 740 nm, and between 2.4% to 8.4% for wavelengths between 741 nm to 780 nm.

32. The semiconductor light emitting device of claim 20, wherein the third unsaturated light has a spectral power distribution that falls between 3.9% to 30.6% for wavelengths between 380 nm to 420 nm, 100% for wavelengths between 421 nm to 460 nm, between 112.7% to 553.9% for wavelengths between 461 nm to 500 nm, between 306.2% to 2660.6% for wavelengths between 501 nm to 540 nm, between 395.1% to 4361.9% for wavelengths between 541 nm to 580 nm, between 318.2% to 3708.8% for wavelengths between 581 nm to 620 nm, between 245% to 2223.8% for wavelengths between 621 nm to 660 nm, between 138.8% to 712.2% for wavelengths between 661 nm to 700 nm, between 39.5% to 285.6% for wavelengths between 701 nm to 740 nm, and between 10.3% to 99.6% for wavelengths between 741 nm to 780 nm.

33. The semiconductor light emitting device of claim 20, wherein the drive circuit is responsive to input from one or more of an end user of the semiconductor light emitting device and one or more sensors measuring a characteristic associated with the performance of the semiconductor light emitting device.

39. The semiconductor light emitting device of claim 20,

wherein the drive circuit is configured to adjust the fourth color point so that it falls within a 7-step MacAdam ellipse around any point on the black body locus having a correlated color temperature between about 1800K and about 3200K;

and

wherein the light emitting device is configured to generate the fourth unsaturated light corresponding to a plurality of points along a predefined path;

wherein;

the light generated at points along about 85% of the predefined path has Ra greater than or equal to about 92;

the light generated at points along about 85% of the predefined path has R9 greater than or equal to about 70;

or both.

41. The semiconductor light emitting device of claim 20, wherein the third LED string comprises a blue LED with a peak wavelength of between about 440 nm and about 465 nm.

34. A method of forming a light emitting apparatus, the method comprising:

providing a substrate,

mounting a first LED, a second LED, and a third LED on the substrate,

providing first, second, and third luminophoric mediums in illuminative communication with the first, second, and third LEDs, respectively,

wherein a combined light emitted by the first, second, and third LEDs and the first, second, and third luminophoric mediums together has a fourth color point that falls within a 7-step MacAdam ellipse around any point on the black body locus having a correlated color temperature between about 1800K and about 3200K; and

wherein the second LED and the second luminophoric medium are configured to emit combined light having a spectral power distribution that falls between 0.0% to 14.8% for wavelengths between 380 nm to 420 nm, between 2.1% to 15% for wavelengths between 421 nm to 460 nm, between 2.0% to 6.7% for wavelengths between 461 nm to 500 nm, between 1.4% to 12.2% for wavelengths between 501 nm to 540 nm, between 8.7% to 24.7% for wavelengths between 541 nm to 580 nm, between 48.5% and 102.8% for wavelengths between 581 nm to 620 nm, 100% for wavelengths between 621 nm to 660 nm, between 1.8% to 74.3% for wavelengths between 661 nm to 700 nm, between 0.5% to 29.5% for wavelengths between 701 nm to 740 nm, and between 0.3% to 9.0% for wavelengths between 741 nm to 780 nm.

35. The method of claim 34, wherein

the first LED and the first luminophoric medium are configured to emit combined light having a first color point within a white color range defined by a polygonal region on the 1931 CIE Chromaticity Diagram defined by the following ccx, ccy color coordinates:

(0.4006, 0.4044), (0.3736, 0.3874), (0.3670, 0.3578), (0.3898, 0.3716);

the second LED and the second luminophoric medium are configured to emit combined light having a second color point within a red color range defined by the spectral locus between the constant CCT line of 1600K and the line of purples, the line of purples, a line connecting the ccx, ccy color coordinates (0.61, 0.21) and (0.47, 0.28), and the constant CCT line of 1600K; and

the third LED and the third luminophoric medium are configured to emit combined light having a third color point within a cyan color range defined by a line connecting the ccx, ccy color coordinates (0.18, 0.55) and (0.27, 0.72), the constant CCT line of 9000K, the Planckian locus between 9000K and 1800K, the constant CCT line of 1800K, and the spectral locus.

36. The method of claim 34, wherein

the first, second, and third LEDs and first, second, and third luminophoric mediums are provided as phosphor-coated blue light emitting device chips.

37. The method of claim 34, wherein one or more of the first, second, and third luminophoric mediums are provided in positions remotely located from the first, second, and third LEDs, respectively.

38. The method of claim 37, wherein the first, second, and third luminophoric mediums are provided in positions remotely located from the first, second, and third LEDs, respectively.

42. The method of claim 34, wherein the third LED comprises a blue LED with a peak wavelength of between about 440 nm and about 465 nm.