White light apparatus with enhanced color contrast

Patent metadata

Field	Value
Publication number	US-9954145-B2
Application number	US-201414295486-A
Country	US
Kind code	B2
Filing date	Jun 4, 2014
Priority date	Aug 2, 2004
Publication date	Apr 24, 2018
Grant date	Apr 24, 2018

Abstract

A lighting apparatus for emitting white light including a semiconductor light source emitting radiation with a peak emission between from about 250 nm to about 500 nm and a first phosphor having a peak emission between about 550 and 615 nm, wherein an overall emission spectrum of the lighting apparatus has a depression between about 550 and 615 nm, whereby the red-green color contrast is increased versus a reference illuminant.

First claim

What is claimed is:

1. A lighting apparatus for emitting white light having enhanced red-green color contrast and comprising:
a semiconductor light source emitting radiation having a peak emission in the range of from about 250 to 500 nm;
a phosphor material radiationally coupled to said light source comprising a first phosphor having a peak emission between about 550 to 615 nm, a second phosphor being a red phosphor having a peak emission in the range of from about 615 nm to 670 nm, and a third phosphor being a blue phosphor having a peak emission the range of from about 450 to 550 nm;
a filter comprised of a layer of neodymium glass that prevents a portion of radiation emitted by the first phosphor material from being emitted by the apparatus while substantially permitting the emission of radiation from the lighting apparatus in emission wavelengths other than between 550 and 615 nm; and
wherein said filter is at least one of embedded in an encapsulant surrounding said phosphor material, positioned on top of an encapsulant or shell surrounding said phosphor material, and positioned directly on a layer of said phosphor material.

2. The lighting apparatus of claim 1 , wherein said filter functions such that an overall emission spectrum of the lighting apparatus has a depression between about 550 and 615 nm, said depression extending to between about 5% and 25% of the highest intensity of the emission spectrum of the lighting apparatus in the region from 400 to 700 nm.

3. The lighting apparatus of claim 2 , wherein the depression extends to between about 10% and 20% of the highest intensity of the emission spectrum of the lighting apparatus in the region from 400 to 700 nm.

4. The lighting apparatus of claim 1 , wherein said first phosphor comprises at least one of a garnet phosphor doped with Ce 3+ and a silicate phosphor doped with Eu 2+ .

5. The lighting apparatus of claim 1 , wherein said lighting apparatus has a general (R a ) CRI of at least 80.

6. The lighting apparatus of claim 1 , wherein said light source has a peak emission at a wavelength less than 450 nm.

7. The lighting apparatus of claim 1 , wherein said red phosphor comprises at least one of 3.5MgO*0.5MgF 2 *GeO 2 :Mn 4+ , Ca 1−2e−f Ce e (Li,Na) e Eu f AlSiN 3 , where 0≤e≤0.2, 0≤f≤0.2, e+f>0; or Ca 1−g−h−i Ce g (Li,Na) h Eu i Al 1+g−h Si 1−g+h N 3 where 0≤g≤0.2, 0<h≤0.4, 0≤i≤0.2, g+i>0; CaAlSiN 3 :Eu 2+ and A 2 [MF 6 ]:Mn 4+ where A=Li, Na, K, Rb or Cs and M=Ge, Si, Sn, Ti or Zr.

8. The lighting apparatus of claim 1 , wherein said semiconductor light source comprises a nitride compound semiconductor represented by the formula In i Ga j Al k N, where 0≤i; 0≤j, 0≤k, and i+j+k=1.

9. The lighting apparatus of claim 1 , wherein the phosphor material is at least one of coated on the surface of the light source, and dispersed in an encapsulant surrounding the light source and the phosphor material.

10. The lighting apparatus of claim 1 , further comprising a reflector.

11. The lighting apparatus of claim 1 , wherein said layer is continuous.

12. The lighting apparatus of claim 1 , wherein said apparatus has a CCT of from 2500 to 7500 K.

13. The lighting apparatus of claim 1 , wherein a CCT of said apparatus is higher than 3000K.

14. The lighting apparatus of claim 1 , wherein a color point of said apparatus lies substantially on the black body locus within 0.020 units in the vertical direction on the 1931 CIE Diagram.

15. The lighting apparatus of claim 1 , wherein said neodymium glass includes between about 1 and 10% by weight Nd 2 O 3 .

16. The lighting apparatus of claim 11 , wherein said continuous layer has a thickness between about 0.5 and 1.5 mm.

17. The lighting apparatus of claim 1 , having a revealness of at least about 88.

18. The lighting apparatus of claim 1 , wherein said filter provides a revealness increase of at least about 21.

19. The lighting apparatus of claim 1 , having a gamut area index (GAI) of at least about 43.

20. The lighting apparatus of claim 1 , wherein said filter provides a gamut area index (GAI) increase of at least about 12.

21. The lighting apparatus of claim 1 , wherein said filter provides increased red-green light contrast.

22. A method for making a lighting apparatus for emitting white light having enhanced red-green color contrast, the method including the steps of:
providing a light source emitting radiation having a peak emission at from about 250 to 500 nm;
providing a phosphor material comprising: a first phosphor material having a peak emission between about 550 and 615 nm, a second phosphor being a red phosphor having a peak emission in the range of from about 615 nm to 670 nm, and a third phosphor being a blue phosphor having a peak emission the range of from about 450 to 550 nm;
radiationally coupling said phosphor material to said light source, and
forming a filter comprised of a neodymium glass layer that prevents a portion of radiation emitted by the phosphor material from being emitted by the apparatus while substantially permitting the emission of radiation from the lighting apparatus in emission wavelengths other than between 550 and 615 nm and associating said layer with said light source.

23. The method of claim 22 , wherein said filter functions such that an overall emission spectrum of the lighting apparatus has a depression between about 550 and 615 nm, said depression extending to between about 5% and 25% of the highest intensity of the emission spectrum of the lighting apparatus in the region from 400 to 700 nm.

24. A light bulb including an optical element shaped to receive at least some light from at least one LED, wherein the optical element forms an external surface of the light bulb spaced remotely located from the at least one LED and defines an interior containing the LED and wherein the optical element filters the light to exhibit a spectral notch after being affected by the optical element, and wherein the optical element comprises
a filtering material comprised of neodymium containing SiO 2 glass which is of at least a portion of light emitted by the LED and which filters at least a portion of the transmissive light to exhibit a spectral depression.

25. The optical element of claim 24 wherein the light is visible.

26. The optical element of claim 25 wherein the spectral notch occurs between the wavelengths of 550 nm and 615 nm.

27. The optical element of claim 24 further comprising phosphor material to receive at least a portion of emissions in association with at least one LED chip.

28. An LED system comprising: at least one LED; and a filter according to claim 1 arranged to affect light form the at least one LED; wherein light intensity is comparatively reduced by the optical element within a predetermined portion of a visible spectrum of light emitted by the LED system.

29. The LED system of claim 28 , further comprising at least one phosphor and wherein the light is emitted by the at least one LED in combination with the at least one phosphor.

30. The LED system of claim 28 , wherein the light intensity is comparatively reduced by a peak amount between 5% and about 25%.

31. The LED system of claim 28 , wherein a center wavelength for the spectral notch is between 550 and 615 nm.

32. The LED system of claim 28 wherein said filter compri

Assignees

• Ge Lighting Solutions Llc

Inventors

• Radkov Emil Vergilov
• Hausmann Ilona Elisabeth
• Publicover Derek Allen

Classifications

• H10W90/756

  between a chip and a stacked lead frame, conducting package substrate or heat sink · CPC title

• C09K11/7787

  Oxides (C09K11/7785 takes precedence) · CPC title

• C09K11/7786

  with alkaline earth metals · CPC title

• C09K11/7736

  Vanadates; Chromates; Molybdates; Tungstates · CPC title

• C09K11/0883

  Arsenides; Nitrides; Phosphides · CPC title