Solid state lighting devices including light mixtures

• US 8,998,444 B2
• Filed: 06/25/2009
• Issued: 04/07/2015
• Est. Priority Date: 04/18/2006
• Status: Active Grant

• Current Assignee: IDEAL Industries Lighting, LLC (Ideal Industries Incorporated)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Roberts, John, Negley, Gerald H., van de Ven, Antony P., Chakraborty, Arpan, Keller, Bernd, Le Toquin, Ronan P.
• Primary Examiner(s): Mai, Anh
• Assistant Examiner(s): APENTENG, JESSICA MCMILLAN
• Application Number:
  US12/491,654
• Publication Number:
  US 20100079059A1
• Time in Patent Office: 2,112 Days
• Field of Search: 362/231, 362/235, 362/800, 362/84, 313/503
• US Class Current: 362/231
• CPC Class Codes: F21K 9/00 Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
• CPC Class Codes: F21S 4/20 with light sources held by or within elongate supports
• CPC Class Codes: F21Y 2103/10 comprising a linear array of point-like light-generating elements
• CPC Class Codes: F21Y 2105/10 comprising a two-dimensional array of point-like light-generating elements
• CPC Class Codes: F21Y 2105/12 characterised by the geometrical disposition of the light-generating elements, e.g. arranging light-generating elements in differing patterns or densities
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/50 Wavelength conversion elements
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

A solid state lighting apparatus includes a plurality of light emitting diodes (LEDs) including at least a first LED and a second LED. Chromaticities of the first and second LEDs are selected so that a combined light generated by a mixture of light from the pair of LEDs has about a target chromaticity. The first LED may include a first LED chip that emits light in the blue portion of the visible spectrum and a phosphor that emits red light in response to blue light emitted by the first LED chip. The second LED emits light having a color point that is above the planckian locus of a 1931 CIE Chromaticity diagram, and in particular may have a yellow green, greenish yellow or green hue.

Claims

1. A solid state lighting apparatus comprising:

a plurality of light emitting diodes (LEDs) including at least a first LED and a second LED, wherein a combined light generated by a mixture of light from the pair of LEDs has about a target chromaticity,

wherein the first LED includes a first LED chip that emits light in the blue or green portions of the visible spectrum and includes a phosphor that emits red light in response to light emitted by the first LED chip, and the second LED emits light having a color point that is above the planckian locus of a 1931 CIE Chromaticity diagram,

wherein the second LED includes a second LED chip that emits light in the blue portion of the visible spectrum and includes a second phosphor that is configured to emit yellow light in response to the light emitted by the second LED chip, and

wherein the first LED emits light that is a combination of the blue or green portions of the visible spectrum from the first LED chip and the red light emitted by the phosphor.

2. The solid state lighting apparatus of claim 1, wherein the color point of the second LED is outside a ten step Macadam ellipse from any point on the planckian locus.

3. 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 LED and the phosphor and the color point of light emitted by the second LED crosses the planckian locus between about 2500 Kelvin and 4500 Kelvin.

4. The solid state lighting device of claim 1, wherein the second LED includes a second LED chip that emits substantially saturated light having a dominant wavelength between about 500 nm and 550 nm.

5. The solid state lighting apparatus of claim 1, wherein the second LED chip has a dominant wavelength of from about 430 nm to about 470 nm, and wherein the second phosphor emits light having a dominant wavelength from about 550 nm to about 590 nm.

6. The solid state lighting apparatus of claim 1, wherein combined light emitted by the second LED chip and the second phosphor would, in an absence of any additional light, produce a sub-mixture of light having x, y color coordinates which define a point which is within an area on a 1931 CIE Chromaticity Diagram 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.

7. The solid state lighting apparatus of claim 1, wherein the first LED chip has a dominant wavelength from about 500 nm to about 550 nm,

8. The solid state lighting apparatus of claim 7, wherein the second LED chip has a dominant wavelength from about 500 nm to about 550 nm, wherein the phosphor comprises a first phosphor, and wherein the second LED further comprises a second phosphor that emits yellow light in response to light emitted by the second LED chip.

9. The solid state lighting apparatus of claim 1, wherein the first LED chip has a dominant wavelength from about 500 nm to about 550 nm.

10. The solid state lighting apparatus of claim 1, wherein the first LED chip has a dominant wavelength from about 440 nm to about 460 nm, and wherein the phosphor emits light having a dominant wavelength from about 600 nm to about 630 nm in response to light emitted by the first LED chip.

11. The solid state lighting apparatus of claim 10, wherein the second LED chip has a dominant wavelength from about 440 nm to about 460 nm, and wherein the second LED comprises a second phosphor that emits light having a dominant wavelength from about 550 nm to about 590 nm in response to light emitted by the second LED chip.

12. The solid state lighting apparatus of claim 1, further comprising a third LED that emits light in the blue or green portion of the visible spectrum and that has a dominant wavelength that is at least about 10 nm greater than a dominant wavelength of the first LED.

13. The solid state lighting apparatus of claim 12, wherein the third LED has a dominant wavelength that is at least about 20 nm greater than the dominant wavelength of the first LED.

14. The solid state lighting apparatus of claim 1, further comprising a third LED that emits light in the red portion of the visible spectrum.

15. The solid state lighting apparatus of claim 1, further comprising a plurality of first LEDs and a plurality of second LEDs, wherein the first LEDs and the second LEDs are arranged in respective metameric pairs of LEDs, and wherein light emitted by each of the respective metameric pairs of LEDs has about the target chromaticity.

16. A solid state lighting apparatus comprising:

a plurality of light emitting diodes (LEDs),

wherein chromaticities of the LEDs are selected so that a combined light generated by a mixture of light emitted of the LEDs has about a target chromaticity,

wherein the plurality of LEDs comprises a first LED including a first LED chip that emits light in the blue portion of the visible spectrum and a first phosphor that emits red light in response to blue light emitted by the first LED chip, and

a second LED including a second LED chip that emits light in the blue portion of the visible spectrum and that includes a second phosphor that emits yellow light in response to light emitted by the second LED chip wherein a combined light emitted by the second LED chip and the second phosphor falls outside a 10-step Macadam ellipse about a point on the planckian locus on a 1931 CIE Chromaticity diagram.

17. The solid state lighting apparatus of claim 16, wherein the first LED and the second LED are arranged in the solid state lighting device as a metameric pair.

18. The solid state lighting apparatus of claim 16, wherein the target chromaticity falls within a ten step Macadam ellipse of a point on the planckian locus of a 1931 CIE diagram.

19. The solid state lighting apparatus of claim 16, wherein the second LED comprises a second LED chip that emits saturated light in the blue portion of the visible spectrum and a second phosphor that emits yellow light in response to blue light emitted by the second LED chip, and wherein the combined light emitted by the second LED chip and the second phosphor would, in an absence of any additional light, produce a sub-mixture of light having x, y color coordinates which define a point which is within an area on a 1931 CIE Chromaticity Diagram 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.

20. The solid state lighting apparatus of claim 16, wherein the combined light emitted by the first LED chip and the first phosphor would, in an absence of any additional light, produce a sub-mixture of light having x, y color coordinates which define a point which is within purplish red or red-purple region on a 1931 CIE Chromaticity Diagram.

21. The solid state lighting apparatus of claim 16, wherein a line segment on a 1931 CIE Chromaticity diagram between a color point of combined light emitted by the first LED chip and the phosphor and the color point of light emitted by the second LED crosses the planckian locus between about 2500 Kelvin and 4500 Kelvin.

22. The solid state lighting apparatus of claim 16, wherein the first LED chip has a dominant wavelength from about 440 nm to about 460 nm, and wherein the phosphor emits light having a dominant wavelength from about 600 nm to about 630 nm in response to light emitted by the first LED chip.

23. An illumination module, comprising:

a plurality of light emitting diodes (LEDs) including a metameric pair of LEDs, wherein chromaticities of the LEDs of the metameric pair are selected so that a combined light generated by a mixture of light from each of the LEDs of the metameric pair comprises light having about a target chromaticity, the metameric pair comprising a first LED including a first LED chip that emits light in the blue portion of the visible spectrum and a phosphor that emits red light in response to blue light emitted by the first LED chip, and a second LED that emits non-white light that in the absence of other light appears green, yellowish-green or yellow-green,

wherein the second LED comprises a second LED chip that emits blue light and a phosphor that emits yellow light in response to the blue light emitted by the second LED chip.

24. A solid state lighting apparatus comprising:

a plurality of light emitting diodes (LEDs) including at least a first LED and a second LED;

wherein a combined light generated by a mixture of light from the pair of LEDs has about a target chromaticity;

wherein the first LED includes a first LED chip that emits light in the blue or green portions of the visible spectrum and includes a phosphor that emits red light in response to light emitted by the first LED chip,

wherein the first LED emits light that is a combination of the blue or green portions of the visible spectrum from the first LED chip and the red light emitted by the phosphor,

wherein the combined light of the first LED chip and the phosphor has a first color point,

wherein the second LED emits light having a second color point; and

wherein a line segment on a 1931 CIE Chromaticity diagram between the first color point and the second color point crosses the planckian locus between about 2500 Kelvin and 4500 Kelvin.

25. The solid state lighting apparatus of claim 24, wherein the second LED chip has a dominant wavelength of from about 430 nm to about 500 nm.

26. The solid state lighting apparatus of claim 25, wherein the second LED chip has a dominant wavelength of from about 480 nm to about 500 nm.

27. The solid state lighting apparatus of claim 26, wherein the second LED chip has a dominant wavelength of from about 490 nm to about 500 nm.

28. The solid state lighting apparatus of claim 24, wherein the color point of the second LED is outside a ten step Macadam ellipse from any point on the planckian locus.