Phosphor composition and method for producing the same, and light-emitting device using the same
View Patent ↗A light-emitting device of the present application includes a light-emitting element and a phosphor layer. Output light of the device is white light, which contains red, green, and blue light-emitting components emitted by red and green phosphors and a blue light-emitting element, respectively. The phosphor layer includes a phosphor such as a red phosphor, which is a nitridoaluminosilicate-based nitride phosphor, and a green phosphor. The red and green phosphors and the blue light-emitting element have emission peaks from 600 nm to less than 660 nm, from 500 to less than 560 nm, and from 440 nm to less than 500 nm, respectively. The phosphor in the phosphor layer has an excitation peak at a wavelength shorter than that of the emission peak of light emitted by the blue light-emitting element. The phosphor is activated with Eu 2+ or Ce 3+ .
1. A light-emitting device comprising a light-emitting element and a phosphor layer comprising a red phosphor and a green phosphor,
output light containing a red light-emitting component emitted by the red phosphor, a green light-emitting component emitted by the green phosphor, and a light-emitting component emitted by the light-emitting element,
wherein the output light is white light,
the red phosphor is a nitridoaluminosilicate-based nitride phosphor that is activated with Eu 2+ and excited with light emitted by the light-emitting element, and has an emission peak in a wavelength range of 600 nm to less than 660 nm,
the green phosphor is activated either with Eu 2+ or with Ce 3+ and excited with light emitted by the light-emitting element, and has an emission peak in a wavelength range of 500 nm to less than 560 nm,
the light-emitting element is a blue light-emitting element that emits light having an emission peak in a wavelength range of 440 nm to less than 500 nm,
all phosphors contained in the phosphor layer are either phosphors activated with Eu 2+ or phosphors activated with Ce 3+ ,
the red phosphor has an internal quantum efficiency of at least 80% under the excitation of light emitted by the blue light-emitting element,
an excitation spectrum of all the phosphors contained in the phosphor layer has an excitation peak in a wavelength range shorter than a wavelength of the emission peak of light emitted by the blue light-emitting element, and
the phosphor layer does not substantially contain an inorganic phosphor other than a nitride phosphor or an oxynitride phosphor.