Nitride red phosphors and white light emitting diode using rare-earth-co-doped nitride red phosphors
Disclosed are nitride red phosphors and white light emitting diodes using the same. More particularly, the present invention provides a nitride red phosphor with easily controlled composition of phosphor fraction and improved uniformity and color gamut thereof, a method for preparation thereof, a white light emitting diode with excellent color rendition and high light emitting efficiency, and a white light emitting diode package using the same.
1. A nitride red phosphor represented by the following formula 1:
Ba 2-x Re x Al y Si 5-y N 8 [Formula 1]
wherein x and y as molar ratios are defined by 0.0001≦x≦1.0 and 0.001≦y≦5.0, respectively; and Re is at least one selected from rare-earth elements or transition metal elements.
2. The nitride red phosphor according to claim 1 , wherein the nitride red phosphor is activated by a rare-earth element.
3. The nitride red phosphor according to claim 1 , wherein an excitation wavelength of the nitride red phosphor ranges from 300 to 500 nm while an emission wavelength thereof ranges from 500 to 800 nm.
4. The nitride red phosphor according to claim 1 , wherein Re is at least one metal selected from a group consisting of Ce, Pr, Eu, Tb, Yb, Er and Mn.
5. A method for preparation of the nitride red phosphor as set forth in claim 1 , comprising: a first step of heat treating a dried precursor mixture at 500 to 900° C. and ordinary pressure under a gas atmosphere; and a second step of sintering the heat treated mixture at 1,400 to 1,800° C. and ordinary pressure under a gas atmosphere.
6. The method according to claim 5 , wherein the gas is selected from nitrogen, argon, a mixture of hydrogen and nitrogen and a mixture of carbon monoxide and carbon dioxide.
7. A white LED including the nitride red phosphor as set forth in claim 1 , wherein the nitride red phosphor is excited by a light source for an LED at 300 to 500 nm wavelength range to generate an emission wave having a wave band of 500 to 800 nm so that the diode emits the white light using the emission wave.
8. The white LED according to claim 7 , wherein the light source for the LED has a dominant wavelength ranging from 390 to 480 nm.
9. The white LED according to claim 7 , wherein red light emitted by the nitride red phosphor has a peak wavelength ranging from 600 to 680 nm.
10. The white LED according to claim 7 , wherein Re of the nitride red phosphor is Eu, while x and y as molar ratios are defined by 0.0001≦x≦1.0 and 0.001≦y≦5.0, respectively.
11. The white LED according to claim 7 , wherein the nitride red phosphor is combined with a transparent epoxy or silicon resin and applied to a chip constituting the LED light source by a dispensing process.
12. The white LED according to claim 7 , wherein the nitride red phosphor is combined with a transparent epoxy or silicon resin and applied to a chip constituting the LED light source by a transfer molding process.
13. The white LED according to claim 7 , wherein the nitride red phosphor is combined with a transparent epoxy or silicon resin and applied to a chip constituting the LED light source by a sputtering or deposition process.
14. A white LED package including the nitride red phosphor as set forth in claim 1 , wherein the nitride red phosphor is excited by a light source for an LED at 300 to 500 nm wavelength range to generate an emission wave having a wave band of 500 to 800 nm so that the diode package emits the white light using the emission wave.
15. The white LED package according to claim 14 , wherein the package is fabricated in a shell form.
16. The white LED package according to claim 14 , wherein the package is fabricated in a surface-mounted form.
17. The white LED package according to claim 16 , wherein the surface-mounted package has an epoxy lens.