Phosphor, method of producing the same, and light emitting apparatus
View Patent ↗There are provided a phosphor which is a divalent europium-activated oxynitride phosphor substantially represented by General formula (A): Eu a Si b Al c O d N e , a divalent europium-activated oxynitride phosphor substantially represented by General formula (B): MI f Eu g Si h Al k O m N n or a divalent europium-activated nitride phosphor substantially represented by General formula (C): (MII 1-p Eu p )MIIISiN 3 , having a reflectance of light emission in a longer wavelength region of visible light than a peak wavelength of 95% or larger, and a method of producing such phosphor; a nitride phosphor and an oxynitride phosphor which emit light efficiently and stably by the light having a wavelength ranging from 430 to 480 nm from a semiconductor light emitting device by means of a light emitting apparatus using such phosphor, and a producing method of such phosphor; and a light emitting apparatus having stable characteristics and realizing high efficiency.
1. A light converter comprising:
(i) a red-based luminous phosphor having a reflectance of 95% or larger in a region of visible light having wavelengths longer than a peak wavelength of the red-based luminous phosphor and comprising a divalent europium-activated nitride phosphor substantially represented by the formula: (MII 1-p Eu p )MIIIS i N 3 ,
wherein MII comprises at least one alkaline earth metal element selected from the group consisting of Mg, Ca, Sr and Ba, MIII comprises at least one trivalent metal element selected from the group consisting of Al, Ga, In, Sc, Y, La, Gd and Lu, and 0.005≦p≦0.02; and
(ii) a green-based luminous phosphor having a reflectance of 95% or larger in a region of visible light having wavelengths longer than a peak wave length of the green-based luminous phosphor and comprising a divalent europium-activated oxynitride phosphor comprising a β-type SiAlON substantially represented by the formula: Eu a Si b Al c O d N e , wherein 0.005≦a≦0.4, b+c=12, and d+e=16.
2. The light converter according to claim 1 , wherein MIII is at least one element selected from the group consisting of Al, Ga and In.
3. A light emitting apparatus comprising:
a light emitting device that emits a primary light; and
a light converter that absorbs part of said primary light and emits secondary light having a longer wavelength than that of said primary light, said light converter comprising a red-based luminous phosphor and a green-based luminous phosphor,
wherein said red-based luminous phosphor has a reflectance of 95% or larger in a longer wavelength region of visible light than a peak wavelength of the red-based luminous phosphor and comprises a divalent europium-activated nitride phosphor substantially represented by the formula: (MII 1-p Eu p )MIIIS i N 3 ,
wherein MII comprises at least one alkaline earth metal selected from the group consisting of Mg, Ca, Sr and Ba, MIII comprises at least one trivalent metal element selected from the group consisting of Al, Ga, In, Sc, Y, La, Gd and Lu, and 0.005≦p≦0.02, and
wherein said green-based luminous phosphor has a reflectance of 95% or larger in a longer wavelength region of visible light than a peak wavelength of the green-based luminous phosphor and comprises a β-type SiAlON substantially represented by the formula: Eu a Si b Al c O d N e , in which 0.005≦a≦0.4, b+c=12, and d+e=16.
4. The light emitting apparatus according to claim 3 , wherein MIII is at least one element selected from the group consisting of Al, Ga and In.
5. The light emitting apparatus according to claim 3 , wherein said light emitting device is a gallium nitride-based semiconductor device, and primary light from the light-emitting device has a wavelength ranging from 430 to 480 nm.