Nitride-based red-emitting phosphors in RGB (red-green-blue) lighting systems

• US 8,951,440 B2
• Filed: 09/25/2012
• Issued: 02/10/2015
• Est. Priority Date: 05/19/2008
• Status: Expired due to Fees

• Current Assignee: Intematix Corporation
• Original Assignee: Intematix Corporation
• Inventors: Liu, Shengfeng, Tao, Dejie, Yuan, Xianglong, Li, Yi-Qun
• Primary Examiner(s): Koslow, Carol M
• Application Number:
  US13/626,684
• Publication Number:
  US 20130234586A1
• Time in Patent Office: 868 Days
• Field of Search: 252/301.4 F, 252/301.4 H, 313/503, 257/98
• US Class Current: 252/301.4F
• CPC Class Codes: C04B 2235/3206 Magnesium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3208 Calcium oxide or oxide-forming salts thereof, e.g. lime
• CPC Class Codes: C04B 2235/3213 Strontium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3215 Barium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3217 Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
• CPC Class Codes: C04B 2235/3224 Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
• CPC Class Codes: C04B 2235/3286 Gallium oxides, gallates, indium oxides, indates, thallium oxides, thallates or oxide forming salts thereof, e.g. zinc gallate
• CPC Class Codes: C04B 2235/3409 Boron oxide, borates, boric acids, or oxide forming salts thereof, e.g. borax
• CPC Class Codes: C04B 2235/3852 Nitrides, e.g. oxynitrides, carbonitrides, oxycarbonitrides, lithium nitride, magnesium nitride
• CPC Class Codes: C04B 2235/3865 Aluminium nitrides
• CPC Class Codes: C04B 2235/3873 Silicon nitrides, e.g. silicon carbonitride, silicon oxynitride
• CPC Class Codes: C04B 2235/3895 Non-oxides with a defined oxygen content, e.g. SiOC, TiON
• CPC Class Codes: C04B 2235/444 Halide containing anions, e.g. bromide, iodate, chlorite
• CPC Class Codes: C04B 2235/445 Fluoride containing anions, e.g. fluosilicate
• CPC Class Codes: C04B 2235/723 Oxygen content
• CPC Class Codes: C04B 35/58 based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides containing free binder metal C22C29/00
• CPC Class Codes: C04B 35/581 based on aluminium nitride
• CPC Class Codes: C04B 35/584 based on silicon nitride
• CPC Class Codes: C09K 11/0883 Arsenides; Nitrides; Phosphides
• CPC Class Codes: C09K 11/77348 Silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides
• CPC Class Codes: F21Y 2115/10 : Light-emitting diodes [LED]
• CPC Class Codes: H05B 33/12 : Light sources with substantially two-dimensional radiating surfaces
• CPC Class Codes: Y02B 20/00 : Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

Embodiments of the present invention are directed to nitride-based, red-emitting phosphors in red, green, and blue (RGB) lighting systems, which in turn may be used in backlighting displays and warm white-light applications. In particular embodiments, the red-emitting phosphor is based on CaAlSiN₃ type compounds activated with divalent europium. In one embodiment, the nitride-based, red emitting compound contains a solid solution of calcium and strontium compounds (Ca,Sr)AlSiN₃:Eu²⁺, wherein the impurity oxygen content is less than about 2 percent by weight. In another embodiment, the (Ca,Sr)AlSiN₃:Eu²⁺ compounds further contains a halogen in an amount ranging from about zero to about 2 atomic percent, where the halogen may be fluorine (F), chlorine (Cl), or any combination thereof. In one embodiment at least half of the halogen is distributed on 2-fold coordinated nitrogen (N2) sites relative to 3-fold coordinated nitrogen (N3) sites.

Claims

1. A nitride-based, red emitting compound having the formula MAlSiN₃:

Eu²⁺, wherein M is at least one of Ca and Sr, further comprising a halogen whose content ranges from greater than about zero to about 2 atomic percent, wherein at least half of the halogen is distributed on 2-fold coordinated nitrogen (N2) sites relative to 3-fold coordinated nitrogen (N3) sites.

2. The compound of claim 1, wherein the halogen is selected from the group consisting of F and Cl.

3. The compound of claim 1, wherein the impurity oxygen content is less than about 2 percent by weight.

4. The compound of claim 1, wherein the impurity oxygen content is less than about 1.9 percent by weight.

5. The compound of claim 1, wherein the impurity oxygen content is less than about 1.8 percent by weight.

6. The compound of claim 1, wherein the halogen is F.

7. The compound of claim 1, wherein M consists of Ca and Sr.

8. An RGB lighting system for use in a white LED or backlighting display application, the RGB lighting system comprising:

the nitride-based, red-emitting phosphor according to claim 1,

a green phosphor, and

a blue LED emitting in a wavelength ranging from about 400 nm to about 550 nm.

9. The compound of claim 1, wherein at least 80% of the halogen is distributed on 2-fold coordinated nitrogen (N2) sites relative to 3-fold coordinated nitrogen (N3) sites.

10. The compound of claim 9, wherein the impurity oxygen content is less than about 2 percent by weight.

11. The compound of claim 9, wherein the impurity oxygen content is less than about 1.9 percent by weight.

12. The compound of claim 9, wherein the impurity oxygen content is less than about 1.8 percent by weight.

13. The compound of claim 9, wherein the halogen is selected from the group consisting of F and Cl.

14. The compound of claim 9, wherein the halogen is F.

15. The compound of claim 9, wherein M consists of Ca and Sr.

16. An RGB lighting system for use in a white LED or backlighting display application, the RGB lighting system comprising:

the nitride-based, red-emitting phosphor according to claim 9,

a green phosphor, and

a blue LED emitting in a wavelength ranging from about 400 nm to about 550 nm.